diff --git a/src/controllers/task.controller.js b/src/controllers/task.controller.js
index 671c487..e1d2ffc 100644
--- a/src/controllers/task.controller.js
+++ b/src/controllers/task.controller.js
@@ -190,12 +190,12 @@ class TaskController {
   async updateTeamMember(req, res, next) {
     try {
       const taskId = req.body.taskId || req.params.taskId;
-      const memberId = req.body.memberId || req.params.memberId;
+      const userId = req.body.userId || req.params.userId;
       const { role } = req.body;
 
       const result = await taskService.modifyMemberRole(
         parseInt(taskId),
-        parseInt(memberId),
+        parseInt(userId),
         role
       );
 
diff --git a/src/repositories/task.repository.js b/src/repositories/task.repository.js
index 68948d3..ed1b82e 100644
--- a/src/repositories/task.repository.js
+++ b/src/repositories/task.repository.js
@@ -178,21 +178,21 @@ class TaskRepository {
   }
 
   // 멤버 존재 여부 확인
-  async findMemberInTask(taskId, memberId) {
+  async findMemberInTask(taskId, userId) {
     return await prisma.member.findFirst({
       where: {
-        id: memberId,
-        taskId: taskId
+        taskId: parseInt(taskId),
+        userId: parseInt(userId) 
       }
     });
   }
 
   // 나머지 멤버 역할 리셋
-  async resetOtherMembersRole(taskId, memberId, tx) {
+  async resetOtherMembersRole(taskId, userId, tx) {
     return await tx.member.updateMany({
       where: {
-        taskId: taskId,
-        id: { not: memberId },
+        taskId: parseInt(taskId),
+        userId: { not: parseInt(userId) }, 
       },
       data: {
         role: false,
@@ -203,7 +203,7 @@ class TaskRepository {
   // 대상 멤버 역할 업데이트
   async updateMemberRole(memberId, isAdmin, tx) {
     return await tx.member.update({
-      where: { id: memberId },
+      where: { id: memberId }, // userId는 중복될 수 있으므로(다른 과제 등) id(PK) 사용
       data: { role: isAdmin },
     });
   }
diff --git a/src/routes/task.route.js b/src/routes/task.route.js
index ac87a9f..050d3c5 100644
--- a/src/routes/task.route.js
+++ b/src/routes/task.route.js
@@ -30,8 +30,8 @@ router.get("/:taskId", authenticate, taskController.getTaskDetail);
 // GET /api/v1/task?sort=우선순위 -- 과제 목록 조회
 router.get("/", authenticate, taskController.getTasks);
 
-// PATCH /api/v1/task/:taskId/member/:memberId -- 팀원 정보 수정
-router.patch("/:taskId/member/:memberId", authenticate, taskController.updateTeamMember);
+// PATCH /api/v1/task/:taskId/member/:userId -- 팀원 정보 수정
+router.patch("/:taskId/member/:userId", authenticate, taskController.updateTeamMember);
 
 // POST /api/v1/task/:taskId/subTask -- 단일 세부 과제 추가
 router.post("/:taskId/subTask", authenticate, taskController.addSubTask)
diff --git a/src/services/task.service.js b/src/services/task.service.js
index a6374b0..21b9c16 100644
--- a/src/services/task.service.js
+++ b/src/services/task.service.js
@@ -745,19 +745,20 @@ class TaskService {
   }
 
   // 팀원 정보 수정
-  async modifyMemberRole(taskId, memberId, role) {
-    const member = await taskRepository.findMemberInTask(taskId, memberId);
-    if (!member) throw new NotFoundError("멤버를 찾을 수 없음");
+  async modifyMemberRole(taskId, userId, role) {
+    const member = await taskRepository.findMemberInTask(taskId, userId);
+  
+  if (!member) throw new NotFoundError("해당 과제에서 해당 유저를 찾을 수 없음");
 
-    const isAdmin = role === 1;
+  const isAdmin = role === 1;
 
-    return await prisma.$transaction(async (tx) => {
-      if (isAdmin) {
-        await taskRepository.resetOtherMembersRole(taskId, memberId, tx);
-      }
+  return await prisma.$transaction(async (tx) => {
+    if (isAdmin) {
+      await taskRepository.resetOtherMembersRole(taskId, userId, tx);
+    }
 
-      return await taskRepository.updateMemberRole(memberId, isAdmin, tx);
-    });
+    return await taskRepository.updateMemberRole(member.id, isAdmin, tx);
+  });
   }
 
   // 단일 세부 과제 생성 서비스
diff --git a/src/swagger/swagger.yml b/src/swagger/swagger.yml
index e161884..6707b6e 100644
--- a/src/swagger/swagger.yml
+++ b/src/swagger/swagger.yml
@@ -1729,7 +1729,7 @@ paths:
           description: 서버 내부 오류
 
   # 팀원 정보(역할) 수정
-  /api/v1/task/{taskId}/member/{memberId}:
+  /api/v1/task/{taskId}/member/{userId}:
     patch:
       tags:
         - Task
@@ -1744,7 +1744,7 @@ paths:
           schema:
             type: integer
         - in: path
-          name: memberId
+          name: userId
           required: true
           schema:
             type: integer
@@ -1754,12 +1754,12 @@ paths:
           application/json:
             schema:
               type: object
-              required: [taskId, memberId, role]
+              required: [taskId, userId, role]
               properties:
                 taskId:
                   type: integer
                   example: 1
-                memberId:
+                userId:
                   type: integer
                   example: 5
                 role: