diff --git a/src/components/pages/premium-study-detail-page.tsx b/src/components/pages/premium-study-detail-page.tsx
index cac6719d..7cda1c5c 100644
--- a/src/components/pages/premium-study-detail-page.tsx
+++ b/src/components/pages/premium-study-detail-page.tsx
@@ -42,8 +42,11 @@ export default function PremiumStudyDetailPage({
 
   const activeTab = (searchParams.get('tab') as StudyTabValue) || 'intro';
 
-  const { data: studyDetail, isLoading } =
-    useGroupStudyDetailQuery(groupStudyId);
+  const {
+    data: studyDetail,
+    isLoading,
+    refetch: refetchStudyDetail,
+  } = useGroupStudyDetailQuery(groupStudyId);
 
   const leaderId = studyDetail?.basicInfo.leader.memberId;
 
@@ -120,6 +123,7 @@ export default function PremiumStudyDetailPage({
               alert('스터디 삭제에 실패하였습니다.');
             },
             onSettled: () => {
+              refetchStudyDetail().catch(() => {});
               router.push('/premium-study');
               setShowModal(false);
             },
diff --git a/src/features/study/group/api/create-group-study.ts b/src/features/study/group/api/create-group-study.ts
index 66c5c36f..20a8dd00 100644
--- a/src/features/study/group/api/create-group-study.ts
+++ b/src/features/study/group/api/create-group-study.ts
@@ -1,8 +1,8 @@
 import { axiosInstance } from '@/api/client/axios';
-import { GroupStudyFormRequest } from './group-study-types';
+import { GroupStudyCreateRequest } from './group-study-types';
 
-// CS 스터디 매칭 신청
-export const createGroupStudy = async (payload: GroupStudyFormRequest) => {
+// 그룹 스터디 개설
+export const createGroupStudy = async (payload: GroupStudyCreateRequest) => {
   try {
     const res = await axiosInstance.post('/group-studies', payload);
 
diff --git a/src/features/study/group/api/group-study-types.ts b/src/features/study/group/api/group-study-types.ts
index 71c92e42..696da154 100644
--- a/src/features/study/group/api/group-study-types.ts
+++ b/src/features/study/group/api/group-study-types.ts
@@ -56,7 +56,65 @@ export interface BasicInfo {
   updatedAt: string;
 }
 
-// 요청용 BasicInfo (백엔드 request body에서 createdAt, updatedAt 제외됨)
+// ============================================================
+// Create/Update API 공통 타입
+// ============================================================
+
+/** Create/Update API에서 공통으로 사용되는 BasicInfo 필드 */
+export interface BasicInfoCommon {
+  type: StudyType;
+  targetRoles: TargetRole[];
+  maxMembersCount: number;
+  experienceLevels: ExperienceLevel[];
+  method: StudyMethod;
+  regularMeeting: RegularMeeting;
+  location: string;
+  startDate: string;
+  endDate: string;
+  price: number;
+  studyLeaderParticipation: boolean;
+}
+
+/** Create/Update API에서 공통으로 사용되는 Request 구조 */
+export interface GroupStudyRequestCommon {
+  detailInfo: DetailInfo;
+  interviewPost: {
+    interviewPost: string[];
+  };
+  thumbnailExtension: ThumbnailExtension;
+}
+
+// ============================================================
+// Create API 전용 타입
+// ============================================================
+
+/** Create API용 BasicInfo (classification 필수) */
+export interface BasicInfoCreateRequest extends BasicInfoCommon {
+  classification: 'GROUP_STUDY' | 'PREMIUM_STUDY';
+}
+
+/** Create API 전체 Request */
+export interface GroupStudyCreateRequest extends GroupStudyRequestCommon {
+  basicInfo: BasicInfoCreateRequest;
+}
+
+// ============================================================
+// Update API 전용 타입
+// ============================================================
+
+/** Update API용 BasicInfo (classification 없음 - 수정 불가) */
+export type BasicInfoUpdateRequest = BasicInfoCommon;
+
+/** Update API 전체 Request */
+export interface GroupStudyUpdateRequest extends GroupStudyRequestCommon {
+  basicInfo: BasicInfoUpdateRequest;
+}
+
+// ============================================================
+// 기존 타입 (하위 호환성 유지)
+// ============================================================
+
+/** @deprecated BasicInfoCreateRequest 사용 권장 */
 export type BasicInfoRequest = Omit<BasicInfo, 'createdAt' | 'updatedAt'>;
 
 export interface BasicInfoDetail extends BasicInfo {
@@ -162,6 +220,7 @@ export interface ApplyGroupStudyResponse {
   createdAt: string;
 }
 
+/** @deprecated GroupStudyCreateRequest 또는 GroupStudyUpdateRequest 사용 권장 */
 export interface GroupStudyFormRequest {
   basicInfo: BasicInfoRequest;
   detailInfo: DetailInfo;
diff --git a/src/features/study/group/api/update-group-study.ts b/src/features/study/group/api/update-group-study.ts
index 3d4eb0d1..2cccdf1f 100644
--- a/src/features/study/group/api/update-group-study.ts
+++ b/src/features/study/group/api/update-group-study.ts
@@ -1,13 +1,13 @@
 import { axiosInstance } from '@/api/client/axios';
 import {
   GroupStudyCreationResponse,
-  GroupStudyFormRequest,
+  GroupStudyUpdateRequest,
 } from './group-study-types';
 
 // 그룹 스터디 수정
 export const updateGroupStudy = async (
   groupStudyId: number,
-  payload: GroupStudyFormRequest,
+  payload: GroupStudyUpdateRequest,
 ): Promise<GroupStudyCreationResponse> => {
   try {
     const res = await axiosInstance.put<GroupStudyCreationResponse>(
diff --git a/src/features/study/group/const/use-group-study-mutation.ts b/src/features/study/group/const/use-group-study-mutation.ts
index 848ffd30..51fede36 100644
--- a/src/features/study/group/const/use-group-study-mutation.ts
+++ b/src/features/study/group/const/use-group-study-mutation.ts
@@ -1,19 +1,22 @@
 import { useMutation } from '@tanstack/react-query';
 import { createGroupStudy } from '../api/create-group-study';
-import { GroupStudyFormRequest } from '../api/group-study-types';
+import {
+  GroupStudyCreateRequest,
+  GroupStudyUpdateRequest,
+} from '../api/group-study-types';
 import { updateGroupStudy } from '../api/update-group-study';
 
 // 그룹 스터디 개설 mutation
 export const useCreateGroupStudyMutation = () => {
   return useMutation({
-    mutationFn: (payload: GroupStudyFormRequest) => createGroupStudy(payload),
+    mutationFn: (payload: GroupStudyCreateRequest) => createGroupStudy(payload),
   });
 };
 
 // 그룹 스터디 수정 mutation
 export const useUpdateGroupStudyMutation = (groupStudyId: number) => {
   return useMutation({
-    mutationFn: (payload: GroupStudyFormRequest) =>
+    mutationFn: (payload: GroupStudyUpdateRequest) =>
       updateGroupStudy(groupStudyId, payload),
   });
 };
diff --git a/src/features/study/group/model/group-study-form.schema.ts b/src/features/study/group/model/group-study-form.schema.ts
index a9b8c4ba..fa3b61b9 100644
--- a/src/features/study/group/model/group-study-form.schema.ts
+++ b/src/features/study/group/model/group-study-form.schema.ts
@@ -1,5 +1,11 @@
 import { z } from 'zod';
-import { GroupStudyFormRequest } from '../api/group-study-types';
+import {
+  BasicInfoCommon,
+  GroupStudyCreateRequest,
+  GroupStudyFormRequest,
+  GroupStudyRequestCommon,
+  GroupStudyUpdateRequest,
+} from '../api/group-study-types';
 import {
   STUDY_TYPES,
   TARGET_ROLE_OPTIONS,
@@ -127,28 +133,35 @@ export function buildOpenGroupDefaultValues(
   };
 }
 
-export function toOpenGroupRequest(
-  v: GroupStudyFormValues,
-): GroupStudyFormRequest {
+// ============================================================
+// 변환 함수 (내부 헬퍼)
+// ============================================================
+
+/** 공통 BasicInfo 필드 변환 */
+function buildBasicInfoCommon(v: GroupStudyFormValues): BasicInfoCommon {
   const isPremiumStudy = v.classification === 'PREMIUM_STUDY';
+
+  return {
+    studyLeaderParticipation: v.studyLeaderParticipation,
+    type: v.type,
+    targetRoles: v.targetRoles,
+    maxMembersCount: Number(v.maxMembersCount),
+    experienceLevels: v.experienceLevels ?? [],
+    method: v.method,
+    regularMeeting: v.regularMeeting,
+    location: v.location.trim(),
+    startDate: v.startDate.trim(),
+    endDate: v.endDate.trim(),
+    price: isPremiumStudy ? Number(v.price) || 0 : 0,
+  };
+}
+
+/** 공통 Request 구조 변환 */
+function buildCommonRequest(v: GroupStudyFormValues): GroupStudyRequestCommon {
   const thumbnailExt =
     v.thumbnailExtension === 'DEFAULT' ? 'JPG' : v.thumbnailExtension;
 
   return {
-    basicInfo: {
-      studyLeaderParticipation: v.studyLeaderParticipation,
-      classification: v.classification,
-      type: v.type,
-      targetRoles: v.targetRoles,
-      maxMembersCount: Number(v.maxMembersCount),
-      experienceLevels: v.experienceLevels ?? [],
-      method: v.method,
-      regularMeeting: v.regularMeeting,
-      location: v.location.trim(),
-      startDate: v.startDate.trim(),
-      endDate: v.endDate.trim(),
-      price: isPremiumStudy ? Number(v.price) || 0 : 0,
-    },
     detailInfo: {
       thumbnailExtension: thumbnailExt,
       title: v.title,
@@ -161,3 +174,41 @@ export function toOpenGroupRequest(
     thumbnailExtension: thumbnailExt,
   };
 }
+
+// ============================================================
+// Create/Update 전용 변환 함수
+// ============================================================
+
+/** Create API용 Request 변환 */
+export function toCreateRequest(
+  v: GroupStudyFormValues,
+): GroupStudyCreateRequest {
+  return {
+    ...buildCommonRequest(v),
+    basicInfo: {
+      ...buildBasicInfoCommon(v),
+      classification: v.classification,
+    },
+  };
+}
+
+/** Update API용 Request 변환 */
+export function toUpdateRequest(
+  v: GroupStudyFormValues,
+): GroupStudyUpdateRequest {
+  return {
+    ...buildCommonRequest(v),
+    basicInfo: buildBasicInfoCommon(v),
+  };
+}
+
+// ============================================================
+// 기존 함수 (하위 호환성 유지)
+// ============================================================
+
+/** @deprecated toCreateRequest 또는 toUpdateRequest 사용 권장 */
+export function toOpenGroupRequest(
+  v: GroupStudyFormValues,
+): GroupStudyFormRequest {
+  return toCreateRequest(v);
+}
diff --git a/src/features/study/group/ui/group-study-form-modal.tsx b/src/features/study/group/ui/group-study-form-modal.tsx
index ec98daec..ff19a2dd 100644
--- a/src/features/study/group/ui/group-study-form-modal.tsx
+++ b/src/features/study/group/ui/group-study-form-modal.tsx
@@ -20,7 +20,8 @@ import {
   buildOpenGroupDefaultValues,
   GroupStudyFormValues,
   StudyClassification,
-  toOpenGroupRequest,
+  toCreateRequest,
+  toUpdateRequest,
 } from '../model/group-study-form.schema';
 import { useGroupStudyDetailQuery } from '../model/use-study-query';
 
@@ -140,7 +141,7 @@ export default function GroupStudyFormModal({
 
   const handleCreate = async (values: GroupStudyFormValues) => {
     try {
-      const body = toOpenGroupRequest(values);
+      const body = toCreateRequest(values);
       const created = await createGroupStudy(body);
 
       if (values.thumbnailFile) {
@@ -166,7 +167,7 @@ export default function GroupStudyFormModal({
 
   const handleEdit = async (values: GroupStudyFormValues) => {
     try {
-      const body = toOpenGroupRequest(values);
+      const body = toUpdateRequest(values);
       const updated = await updateGroupStudy(body);
 
       if (values.thumbnailFile) {