diff --git a/src/main/java/shop/fevertime/backend/api/ChatApiController.java b/src/main/java/shop/fevertime/backend/api/ChatApiController.java
index 70ed83e..2e6fe18 100644
--- a/src/main/java/shop/fevertime/backend/api/ChatApiController.java
+++ b/src/main/java/shop/fevertime/backend/api/ChatApiController.java
@@ -4,28 +4,29 @@
 import org.springframework.messaging.handler.annotation.MessageMapping;
 import org.springframework.messaging.simp.SimpMessageSendingOperations;
 import org.springframework.stereotype.Controller;
+import shop.fevertime.backend.domain.ChatRoom;
 import shop.fevertime.backend.dto.ChatMessageDto;
+import shop.fevertime.backend.service.ChatRoomService;
 
 @Controller
 @RequiredArgsConstructor
 public class ChatApiController {
 
-    private final SimpMessageSendingOperations messagingTemplate;
+    private final ChatRoomService chatRoomService;
 
     @MessageMapping("/chat/enter")
-    public void enter(ChatMessageDto messageDto){
-
-        messagingTemplate.convertAndSend("/sub/chat/room/" + messageDto.getRoomId(), messageDto);
+    public void enter(ChatMessageDto messageDto) {
+        chatRoomService.enterRoom(messageDto);
     }
 
     @MessageMapping("/chat/message")
     public void message(ChatMessageDto messageDto) {
-        messagingTemplate.convertAndSend("/sub/chat/room/" + messageDto.getRoomId(), messageDto);
+        chatRoomService.sendMsg(messageDto);
     }
 
     @MessageMapping("/chat/exit")
     public void exit(ChatMessageDto messageDto) {
-        messagingTemplate.convertAndSend("/sub/chat/room/" + messageDto.getRoomId(), messageDto);
+        chatRoomService.exitRoom(messageDto);
     }
 
 }
\ No newline at end of file
diff --git a/src/main/java/shop/fevertime/backend/domain/ChatRoom.java b/src/main/java/shop/fevertime/backend/domain/ChatRoom.java
index e9a3d12..05b4b59 100644
--- a/src/main/java/shop/fevertime/backend/domain/ChatRoom.java
+++ b/src/main/java/shop/fevertime/backend/domain/ChatRoom.java
@@ -9,7 +9,7 @@
 @Getter
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
 @Entity
-public class ChatRoom extends BaseTimeEntity{
+public class ChatRoom extends BaseTimeEntity {
 
     @Id
     @GeneratedValue(strategy = GenerationType.AUTO)
@@ -23,9 +23,21 @@ public class ChatRoom extends BaseTimeEntity{
     @JoinColumn(name = "user_id")
     private User user;
 
-    public ChatRoom(String name, User user) {
+    @Column(nullable = false)
+    private int userCount;
+
+    public ChatRoom(String name, User user, int userCount) {
         this.name = name;
         this.user = user;
+        this.userCount = userCount;
+    }
+
+    public void addUserCount() {
+        this.userCount++;
+    }
+
+    public void minusUserCount() {
+        this.userCount--;
     }
 
 }
diff --git a/src/main/java/shop/fevertime/backend/dto/ChatMessageDto.java b/src/main/java/shop/fevertime/backend/dto/ChatMessageDto.java
index b3fab72..7647742 100644
--- a/src/main/java/shop/fevertime/backend/dto/ChatMessageDto.java
+++ b/src/main/java/shop/fevertime/backend/dto/ChatMessageDto.java
@@ -6,7 +6,7 @@
 @Getter
 @Setter
 public class ChatMessageDto {
-    private String roomId;
+    private Long roomId;
     private String sender;
     private String message;
 }
diff --git a/src/main/java/shop/fevertime/backend/dto/request/ChatRoomRequestDto.java b/src/main/java/shop/fevertime/backend/dto/request/ChatRoomRequestDto.java
index 7f17a32..b03e6e9 100644
--- a/src/main/java/shop/fevertime/backend/dto/request/ChatRoomRequestDto.java
+++ b/src/main/java/shop/fevertime/backend/dto/request/ChatRoomRequestDto.java
@@ -9,8 +9,5 @@
 @NoArgsConstructor
 public class ChatRoomRequestDto {
     private String name;
-
-    public ChatRoomRequestDto(String name) {
-        this.name = name;
-    }
+    private int userCount;
 }
diff --git a/src/main/java/shop/fevertime/backend/dto/response/ChatRoomResponseDto.java b/src/main/java/shop/fevertime/backend/dto/response/ChatRoomResponseDto.java
index e0ba15d..0083012 100644
--- a/src/main/java/shop/fevertime/backend/dto/response/ChatRoomResponseDto.java
+++ b/src/main/java/shop/fevertime/backend/dto/response/ChatRoomResponseDto.java
@@ -15,12 +15,14 @@ public class ChatRoomResponseDto {
     private String name;
     private String createdDate;
     private String creator;
+    private int userCount;
 
     public ChatRoomResponseDto(ChatRoom chatRoom) {
         this.roomId = chatRoom.getId();
         this.name= chatRoom.getName();
         this.createdDate = chatRoom.getCreatedDate().format(DateTimeFormatter.ofPattern("yyyy-MM-dd"));
         this.creator = chatRoom.getUser().getKakaoId();
+        this.userCount = chatRoom.getUserCount();
     }
 
 }
diff --git a/src/main/java/shop/fevertime/backend/service/ChatRoomService.java b/src/main/java/shop/fevertime/backend/service/ChatRoomService.java
index 478d33f..d1b72f1 100644
--- a/src/main/java/shop/fevertime/backend/service/ChatRoomService.java
+++ b/src/main/java/shop/fevertime/backend/service/ChatRoomService.java
@@ -2,10 +2,12 @@
 
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.messaging.simp.SimpMessageSendingOperations;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 import shop.fevertime.backend.domain.ChatRoom;
 import shop.fevertime.backend.domain.User;
+import shop.fevertime.backend.dto.ChatMessageDto;
 import shop.fevertime.backend.dto.response.ChatRoomResponseDto;
 import shop.fevertime.backend.dto.request.ChatRoomRequestDto;
 import shop.fevertime.backend.exception.ApiRequestException;
@@ -20,6 +22,7 @@
 public class ChatRoomService {
 
     private final ChatRoomRepository chatRoomRepository;
+    private final SimpMessageSendingOperations messagingTemplate;
 
     @Transactional
     public List<ChatRoomResponseDto> getAllRooms() {
@@ -31,7 +34,7 @@ public List<ChatRoomResponseDto> getAllRooms() {
 
     @Transactional
     public void createRoom(ChatRoomRequestDto chatRoomDto, User user) {
-        chatRoomRepository.save(new ChatRoom(chatRoomDto.getName(), user));
+        chatRoomRepository.save(new ChatRoom(chatRoomDto.getName(), user, chatRoomDto.getUserCount()));
     }
 
     @Transactional
@@ -49,4 +52,31 @@ public void deleteRoom(Long roomId, User user) {
         chatRoomRepository.delete(chatRoom);
     }
 
+    @Transactional
+    public void enterRoom(ChatMessageDto messageDto) {
+        ChatRoom chatRoom = chatRoomRepository.findById(messageDto.getRoomId()).orElseThrow(
+                () -> new ApiRequestException("해당 채팅방이 없습니다.")
+        );
+        //인원수 증가
+        chatRoom.addUserCount();
+        //메시지 전송
+        messagingTemplate.convertAndSend("/sub/chat/room/" + messageDto.getRoomId(), messageDto);
+    }
+
+    @Transactional
+    public void sendMsg(ChatMessageDto messageDto) {
+        //메시지 전송
+        messagingTemplate.convertAndSend("/sub/chat/room/" + messageDto.getRoomId(), messageDto);
+    }
+
+    @Transactional
+    public void exitRoom(ChatMessageDto messageDto) {
+        ChatRoom chatRoom = chatRoomRepository.findById(messageDto.getRoomId()).orElseThrow(
+                () -> new ApiRequestException("해당 채팅방이 없습니다.")
+        );
+        //인원수 감소
+        chatRoom.minusUserCount();
+        //메시지 전송
+        messagingTemplate.convertAndSend("/sub/chat/room/" + messageDto.getRoomId(), messageDto);
+    }
 }