diff --git a/src/main/java/com/example/cosmos_serversb/entities/Group.java b/src/main/java/com/example/cosmos_serversb/entities/Group.java
index 4c98291..47ac114 100644
--- a/src/main/java/com/example/cosmos_serversb/entities/Group.java
+++ b/src/main/java/com/example/cosmos_serversb/entities/Group.java
@@ -1,7 +1,10 @@
 //このクラスは仮です
 package com.example.cosmos_serversb.entities;
 
+import com.example.cosmos_serversb.models.SessionManager;
 import com.example.cosmos_serversb.models.Users;
+import com.sun.corba.se.impl.orbutil.graph.Graph;
+import org.hibernate.Session;
 
 import java.util.ArrayList;
 import java.util.HashSet;
@@ -11,8 +14,6 @@
     private String gId;
     private String uri, name;
     private Set<User> members = new HashSet<>();//HashSetでいいのかな？
-
-    //private ArrayList<Request> requests;
     private Set<Request> requests;
 
     public Group(){
@@ -85,10 +86,15 @@
     }
 
     public void addMember(String uId){
-        // User user = new User(uId, uId, "http:test", "hogehoge");
         User user = Users.getInstance().getUserById(uId);
-        members.add(user);
-//        user.addGroups(this);
+        if(user != null) {
+            members.add(user);
+            user.addGroups(this);
+            Session session = SessionManager.getInstance().getSession();
+            session.update(user);
+        }else{
+            //例外処理
+        }
     }
 
 }