diff --git a/frontend/src/hooks/useAuth.ts b/frontend/src/hooks/useAuth.ts
index 8a628b6..fbf9f0e 100644
--- a/frontend/src/hooks/useAuth.ts
+++ b/frontend/src/hooks/useAuth.ts
@@ -19,10 +19,11 @@ export function useAuth() {
   }, [])
 
   const login = async (username: string, password: string) => {
-    const params = new URLSearchParams({ username, password })
-    const r = await guardiaApi.post('/api/auth/login', params, {
-      headers: { 'Content-Type': 'application/x-www-form-urlencoded' }
-    })
+    // JSON 방식 (ITSM은 JSON 로그인만 지원)
+    const r = await guardiaApi.post('/api/auth/login',
+      { username, password },
+      { headers: { 'Content-Type': 'application/json' } }
+    )
     const { access_token } = r.data
     sessionStorage.setItem('gm_token', access_token)
     const me = await guardiaApi.get('/api/auth/me')