diff --git a/apps/common/features/src/pages/(pst)/normal/ui/modify-page.tsx b/apps/common/features/src/pages/(pst)/normal/ui/modify-page.tsx
index 897b72e62..1bff638f8 100644
--- a/apps/common/features/src/pages/(pst)/normal/ui/modify-page.tsx
+++ b/apps/common/features/src/pages/(pst)/normal/ui/modify-page.tsx
@@ -1,5 +1,6 @@
 "use client";
 
+import { useEffect } from "react";
 import { useForm } from "react-hook-form";
 import { zodResolver } from "@hookform/resolvers/zod";
 import { useMutation, useQuery } from "@tanstack/react-query";
@@ -10,7 +11,7 @@ import {
   type PostUpdateFormData,
 } from "@/entities/post";
 import { ENDPOINT } from "@/shared/config";
-import { useAlertStore, useUserStore } from "@/shared/lib";
+import { setCookie, useAlertStore, useUserStore } from "@/shared/lib";
 
 function ModifyPage({ bbsId, pstNo }: { bbsId: string; pstNo: string }) {
   const { setMessage: alert } = useAlertStore((state) => state);
@@ -38,6 +39,10 @@ function ModifyPage({ bbsId, pstNo }: { bbsId: string; pstNo: string }) {
     },
   });
 
+  useEffect(() => {
+    setCookie("atfl-cd-key", "");
+  }, []);
+
   return (
     <div className="card card-border !mt-6">
       <div className="card-header">
diff --git a/apps/common/features/src/pages/(pst)/notice/ui/modify-page.tsx b/apps/common/features/src/pages/(pst)/notice/ui/modify-page.tsx
index 897b72e62..1bff638f8 100644
--- a/apps/common/features/src/pages/(pst)/notice/ui/modify-page.tsx
+++ b/apps/common/features/src/pages/(pst)/notice/ui/modify-page.tsx
@@ -1,5 +1,6 @@
 "use client";
 
+import { useEffect } from "react";
 import { useForm } from "react-hook-form";
 import { zodResolver } from "@hookform/resolvers/zod";
 import { useMutation, useQuery } from "@tanstack/react-query";
@@ -10,7 +11,7 @@ import {
   type PostUpdateFormData,
 } from "@/entities/post";
 import { ENDPOINT } from "@/shared/config";
-import { useAlertStore, useUserStore } from "@/shared/lib";
+import { setCookie, useAlertStore, useUserStore } from "@/shared/lib";
 
 function ModifyPage({ bbsId, pstNo }: { bbsId: string; pstNo: string }) {
   const { setMessage: alert } = useAlertStore((state) => state);
@@ -38,6 +39,10 @@ function ModifyPage({ bbsId, pstNo }: { bbsId: string; pstNo: string }) {
     },
   });
 
+  useEffect(() => {
+    setCookie("atfl-cd-key", "");
+  }, []);
+
   return (
     <div className="card card-border !mt-6">
       <div className="card-header">
diff --git a/apps/common/features/src/widgets/post/ui/post-form.tsx b/apps/common/features/src/widgets/post/ui/post-form.tsx
index fc3912780..e603e91f1 100644
--- a/apps/common/features/src/widgets/post/ui/post-form.tsx
+++ b/apps/common/features/src/widgets/post/ui/post-form.tsx
@@ -257,39 +257,36 @@ function PostForm<T extends PostFormData | PostUpdateFormData>({
                     <FormField
                       control={form.control}
                       name={"popupYnEtc" as FieldPath<T>}
-                      render={({ field }) => (
-                        <FormItem>
-                          <FormControl>
-                            <PeriodSelector
-                              periodCode={
-                                form.getValues().popupYnEtc?.[0]?.pstgPrdSeCd ??
-                                null
-                              }
-                              disabled={
-                                form.getValues("popupYn" as FieldPath<T>) ===
-                                "N"
-                              }
-                              handlePeriodValueChange={(periodCode) => {
-                                field.onChange([
-                                  {
-                                    ...(form.getValues().popupYnEtc?.[0] ?? {}),
-                                    bbsPstgTypeCd: BOARD_POSTING_CODE.팝업게시,
-                                    pstgPrdSeCd: periodCode,
-                                  },
-                                ]);
-                              }}
-                              handlePostingDateChange={(date) => {
-                                field.onChange([
-                                  {
-                                    ...(form.getValues().popupYnEtc?.[0] ?? {}),
-                                    ...date,
-                                  },
-                                ]);
-                              }}
-                            />
-                          </FormControl>
-                        </FormItem>
-                      )}
+                      render={({ field }) => {
+                        const fieldValues = form.getValues().popupYnEtc?.[0];
+                        return (
+                          <FormItem>
+                            <FormControl>
+                              <PeriodSelector
+                                defaultValues={{ ...fieldValues }}
+                                disabled={
+                                  form.getValues("popupYn" as FieldPath<T>) ===
+                                  "N"
+                                }
+                                handlePeriodValueChange={(periodCode, date) => {
+                                  field.onChange([
+                                    {
+                                      ...fieldValues,
+                                      ...date,
+                                      bbsPstgTypeCd:
+                                        BOARD_POSTING_CODE.팝업게시,
+                                      pstgPrdSeCd: periodCode,
+                                    },
+                                  ]);
+                                }}
+                                handlePostingDateChange={(date) => {
+                                  field.onChange([{ ...fieldValues, ...date }]);
+                                }}
+                              />
+                            </FormControl>
+                          </FormItem>
+                        );
+                      }}
                     />
                   </div>
                 </TableCell>
@@ -327,41 +324,37 @@ function PostForm<T extends PostFormData | PostUpdateFormData>({
                     <FormField
                       control={form.control}
                       name={"upndFixYnEtc" as FieldPath<T>}
-                      render={({ field }) => (
-                        <FormItem>
-                          <FormControl>
-                            <PeriodSelector
-                              periodCode={
-                                form.getValues().upndFixYnEtc?.[0]
-                                  ?.pstgPrdSeCd ?? null
-                              }
-                              disabled={
-                                form.getValues("upndFixYn" as FieldPath<T>) ===
-                                "N"
-                              }
-                              handlePeriodValueChange={(periodCode) => {
-                                field.onChange([
-                                  {
-                                    ...(form.getValues().upndFixYnEtc?.[0] ??
-                                      {}),
-                                    bbsPstgTypeCd: BOARD_POSTING_CODE.상단게시,
-                                    pstgPrdSeCd: periodCode,
-                                  },
-                                ]);
-                              }}
-                              handlePostingDateChange={(date) => {
-                                field.onChange([
-                                  {
-                                    ...(form.getValues().upndFixYnEtc?.[0] ??
-                                      {}),
-                                    ...date,
-                                  },
-                                ]);
-                              }}
-                            />
-                          </FormControl>
-                        </FormItem>
-                      )}
+                      render={({ field }) => {
+                        const fieldValues = form.getValues().upndFixYnEtc?.[0];
+                        return (
+                          <FormItem>
+                            <FormControl>
+                              <PeriodSelector
+                                defaultValues={{ ...fieldValues }}
+                                disabled={
+                                  form.getValues(
+                                    "upndFixYn" as FieldPath<T>,
+                                  ) === "N"
+                                }
+                                handlePeriodValueChange={(periodCode, date) => {
+                                  field.onChange([
+                                    {
+                                      ...fieldValues,
+                                      ...date,
+                                      bbsPstgTypeCd:
+                                        BOARD_POSTING_CODE.상단게시,
+                                      pstgPrdSeCd: periodCode,
+                                    },
+                                  ]);
+                                }}
+                                handlePostingDateChange={(date) => {
+                                  field.onChange([{ ...fieldValues, ...date }]);
+                                }}
+                              />
+                            </FormControl>
+                          </FormItem>
+                        );
+                      }}
                     />
                   </div>
                 </TableCell>
@@ -399,41 +392,37 @@ function PostForm<T extends PostFormData | PostUpdateFormData>({
                     <FormField
                       control={form.control}
                       name={"prdPstgYnEtc" as FieldPath<T>}
-                      render={({ field }) => (
-                        <FormItem>
-                          <FormControl>
-                            <PeriodSelector
-                              periodCode={
-                                form.getValues().prdPstgYnEtc?.[0]
-                                  ?.pstgPrdSeCd ?? null
-                              }
-                              disabled={
-                                form.getValues("prdPstgYn" as FieldPath<T>) ===
-                                "N"
-                              }
-                              handlePeriodValueChange={(periodCode) => {
-                                field.onChange([
-                                  {
-                                    ...(form.getValues().prdPstgYnEtc?.[0] ??
-                                      {}),
-                                    bbsPstgTypeCd: BOARD_POSTING_CODE.기간게시,
-                                    pstgPrdSeCd: periodCode,
-                                  },
-                                ]);
-                              }}
-                              handlePostingDateChange={(date) => {
-                                field.onChange([
-                                  {
-                                    ...(form.getValues().prdPstgYnEtc?.[0] ??
-                                      {}),
-                                    ...date,
-                                  },
-                                ]);
-                              }}
-                            />
-                          </FormControl>
-                        </FormItem>
-                      )}
+                      render={({ field }) => {
+                        const fieldValues = form.getValues().prdPstgYnEtc?.[0];
+                        return (
+                          <FormItem>
+                            <FormControl>
+                              <PeriodSelector
+                                defaultValues={{ ...fieldValues }}
+                                disabled={
+                                  form.getValues(
+                                    "prdPstgYn" as FieldPath<T>,
+                                  ) === "N"
+                                }
+                                handlePeriodValueChange={(periodCode, date) => {
+                                  field.onChange([
+                                    {
+                                      ...fieldValues,
+                                      ...date,
+                                      bbsPstgTypeCd:
+                                        BOARD_POSTING_CODE.기간게시,
+                                      pstgPrdSeCd: periodCode,
+                                    },
+                                  ]);
+                                }}
+                                handlePostingDateChange={(date) => {
+                                  field.onChange([{ ...fieldValues, ...date }]);
+                                }}
+                              />
+                            </FormControl>
+                          </FormItem>
+                        );
+                      }}
                     />
                   </div>
                 </TableCell>
@@ -494,25 +483,33 @@ function PostForm<T extends PostFormData | PostUpdateFormData>({
   );
 }
 
+type PostingDate = {
+  pstgBgngDt: string | undefined;
+  pstgEndDt: string | undefined;
+};
+
 const PeriodSelector = ({
-  periodCode,
+  defaultValues,
   disabled,
   handlePeriodValueChange,
   handlePostingDateChange,
 }: {
-  periodCode: string | null;
+  defaultValues?: {
+    pstgPrdSeCd?: string | null;
+    pstgBgngDt?: string | null;
+    pstgEndDt?: string | null;
+  };
   disabled: boolean;
-  handlePeriodValueChange: (periodCode: string) => void;
-  handlePostingDateChange: (date?: {
-    pstgBgngDt: string | undefined;
-    pstgEndDt: string | undefined;
-  }) => void;
+  handlePeriodValueChange: (periodCode: string, date?: PostingDate) => void;
+  handlePostingDateChange: (date?: PostingDate) => void;
 }) => {
-  const handlePeriodCodeChange = (periodCode: string) => {
-    handlePeriodValueChange(periodCode);
-    handlePostingDateChange({
-      pstgBgngDt: undefined,
-      pstgEndDt: undefined,
+  const [periodCode, setPeriodCode] = useState<string | null>(null);
+
+  const onPeriodCodeChange = (periodCode: string) => {
+    setPeriodCode(periodCode);
+    handlePeriodValueChange(periodCode, {
+      pstgBgngDt: `${dayjs().format("YYYY-MM-DD 00:00:00")}`,
+      pstgEndDt: `${dayjs().add(parseInt(periodCode), "day").format("YYYY-MM-DD 23:59:59")}`,
     });
   };
 
@@ -526,7 +523,7 @@ const PeriodSelector = ({
     });
   };
 
-  const postingPeriod = (periodCode: number | null) => {
+  const postingPeriodFormat = (periodCode: number | null) => {
     if (!periodCode) return "";
     if (periodCode === 99) return "상시";
     return `${dayjs().format("YYYY-MM-DD")} ~ ${dayjs()
@@ -538,15 +535,26 @@ const PeriodSelector = ({
     <div className="flex items-center gap-4">
       <CodeSelect
         upCd="PSTGPRDCD"
-        defaultValue={periodCode ?? ""}
-        onValueChange={handlePeriodCodeChange}
+        defaultValue={defaultValues?.pstgPrdSeCd ?? ""}
+        onValueChange={onPeriodCodeChange}
         disabled={disabled}
         placeholder="기간 선택"
       />
-      {!!periodCode && (
+      {periodCode ? (
         <span className="text-lg text-label">
-          게시 기간: <u>{postingPeriod(parseInt(periodCode))}</u>
+          게시 기간: <u>{postingPeriodFormat(parseInt(periodCode))}</u>
         </span>
+      ) : (
+        defaultValues?.pstgBgngDt &&
+        defaultValues?.pstgEndDt && (
+          <span className="text-lg text-label">
+            게시 기간:{" "}
+            <u>
+              {dayjs(defaultValues?.pstgBgngDt).format("YYYY-MM-DD")} ~{" "}
+              {dayjs(defaultValues?.pstgEndDt).format("YYYY-MM-DD")}
+            </u>
+          </span>
+        )
       )}
       {periodCode === "0" && (
         <DateRangePicker handleDateChange={onDateChange} />