diff --git a/apps/cs/app/api/proxy/[...url]/route.ts b/apps/cs/app/api/proxy/[...url]/route.ts
index 7442c702f..abd3ae007 100644
--- a/apps/cs/app/api/proxy/[...url]/route.ts
+++ b/apps/cs/app/api/proxy/[...url]/route.ts
@@ -60,13 +60,18 @@ async function handler(
         [AUTH_USER_ID]: userId,
       });
 
+      const forwardedHost = request.headers.get("x-forwarded-host");
+      const host = request.headers.get("host");
+      const actualHost = forwardedHost || host || new URL(request.url).hostname.toString();
       
+      // 운영 환경에서 domain 설정
+      const domain = actualHost.includes("hasuon.or.kr") ? ".hasuon.or.kr" : actualHost;
 
       if (refreshToken) {
         cookieStore.set(REFRESH_TOKEN, refreshToken, {
           httpOnly: true,
-          sameSite: "lax",
-//          domain: domain,
+          sameSite: "strict",
+          domain: domain,
           path: "/",
         });
       }
diff --git a/packages/common/components/src/ui/header/index.tsx b/packages/common/components/src/ui/header/index.tsx
index 97ed4c151..15b431b6a 100644
--- a/packages/common/components/src/ui/header/index.tsx
+++ b/packages/common/components/src/ui/header/index.tsx
@@ -72,22 +72,51 @@ export function Header({ viewOnly }: { viewOnly?: boolean }) {
       });
       if (!response.ok) throw new Error("Failed to logout");
 
-      // 쿠키 삭제
+      const actualHost = window.location.hostname;
+      
+      // 서브도메인 쿠키 삭제를 위한 루트 도메인 추출
+      const getRootDomain = (hostname: string): string => {
+        // localhost나 IP 주소인 경우
+        if (hostname === "localhost" || /^\d+\.\d+\.\d+\.\d+$/.test(hostname)) {
+          return hostname;
+        }
+        
+        // hasuon.or.kr 도메인인 경우
+        if (hostname.includes("hasuon.or.kr")) {
+          return ".hasuon.or.kr";
+        }
+        
+        // 일반적인 도메인의 경우 루트 도메인 추출 (예: sub.example.com → .example.com)
+        const parts = hostname.split(".");
+        if (parts.length >= 2) {
+          // 마지막 두 부분을 사용 (예: example.com)
+          return `.${parts.slice(-2).join(".")}`;
+        }
+        
+        return hostname;
+      };
+      
+      const domain = getRootDomain(actualHost);
+      const cookieOptions = domain.startsWith(".") || domain === "localhost" 
+        ? { domain } 
+        : {};
+
+      // 쿠키 삭제 (서브도메인 포함)
       if (appConfig.AUTH_USER_ID) {
-        removeCookie(appConfig.AUTH_USER_ID);
+        removeCookie(appConfig.AUTH_USER_ID, cookieOptions);
       }
       if (appConfig.REFRESH_TOKEN) {
-        removeCookie(appConfig.REFRESH_TOKEN);
+        removeCookie(appConfig.REFRESH_TOKEN, cookieOptions);
       }
       if (appConfig.ACCESS_TOKEN) {
-        removeCookie(appConfig.ACCESS_TOKEN);
+        removeCookie(appConfig.ACCESS_TOKEN, cookieOptions);
       }
       if (appConfig.CLAIM_NAME) {
-        removeCookie(appConfig.CLAIM_NAME);
+        removeCookie(appConfig.CLAIM_NAME, cookieOptions);
       }
 
-      removeCookie("site-id-key");
-      removeCookie("site-theme-key");
+      removeCookie("site-id-key", cookieOptions);
+      removeCookie("site-theme-key", cookieOptions);
 
       window.location.href = "/auth/login";
     } catch (error) {