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
+        }
     }
 
 }
diff --git a/src/main/java/com/example/cosmos_serversb/models/Groups.java b/src/main/java/com/example/cosmos_serversb/models/Groups.java
index 94873fc..5d58b66 100644
--- a/src/main/java/com/example/cosmos_serversb/models/Groups.java
+++ b/src/main/java/com/example/cosmos_serversb/models/Groups.java
@@ -18,7 +18,7 @@
     private static String AppName = "cosmos";
 
     private Groups(){
-        sessionFactory = SessionFactoryManager.getInstance().getSessionFactory();
+        //sessionFactory = SessionFactoryManager.getInstance().getSessionFactory();
     }
 
     public static Groups getInstance(){
@@ -84,7 +84,13 @@
     }
 
     public static HashMap<String, String> addMember(String gId, String uId){
-        return null;
+        Session session = SessionManager.getInstance().getSession();
+        Group editGroup = session.load(Group.class, gId);
+        if(editGroup != null) {
+            editGroup.addMember(uId);
+            session.update(editGroup);
+        }
+        return null;//HashMapへの変更が必要
     }
 
     public static HashMap<String, String> deleteMember(String gId, String uId){
diff --git a/src/main/java/com/example/cosmos_serversb/resources/GroupsRest.java b/src/main/java/com/example/cosmos_serversb/resources/GroupsRest.java
index 2714d23..864698f 100644
--- a/src/main/java/com/example/cosmos_serversb/resources/GroupsRest.java
+++ b/src/main/java/com/example/cosmos_serversb/resources/GroupsRest.java
@@ -1,5 +1,7 @@
 package com.example.cosmos_serversb.resources;
 
+import com.example.cosmos_serversb.entities.Group;
+import com.example.cosmos_serversb.entities.User;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import org.hibernate.Session;
@@ -9,6 +11,8 @@
 
 import com.example.cosmos_serversb.models.*;
 
+import java.io.IOException;
+
 @Component
 @Path("/groups")
 public class GroupsRest {
@@ -22,11 +26,27 @@
     }
 
     @POST
-    public String createGroup(@FormParam("name") String name, @FormParam("uId") String uId, @FormParam("token") String token) throws JsonProcessingException{
+    public String createGroup(@FormParam("name") String name, @FormParam("uId") String uId, @FormParam("token") String token) throws IOException {
+        //グループの作成
         SessionManager.getInstance().getSession();
         ObjectMapper mapper = new ObjectMapper();
-        String json = mapper.writeValueAsString(Groups.getInstance().createGroup(name, uId));
+        Group group = Groups.getInstance().createGroup(name, uId);
+        SessionManager.getInstance().closeSession();//一度データベースを更新。
+
+        //グループにメンバーの追加
+        SessionManager.getInstance().getSession();
+        Groups.addMember(group.getgId(), uId);
         SessionManager.getInstance().closeSession();
+        String json = mapper.writeValueAsString(group);//このJSONには、グループを作成したユーザの情報が含まれていません。
+
+        //以下が思うように動かない。
+//        Session session = SessionManager.getInstance().getSession();
+//        Group editedGroup = (Group) session.load(Group.class, group.getgId());//editedGroupの値がおかしい？
+//        String json = mapper.writeValueAsString(editedGroup);
+//        Group tmpGroup = new Group(session.load(Group.class, group.getgId()));
+//        String json = mapper.writeValueAsString( tmpGroup );
+//        SessionManager.getInstance().closeSession();
+
         return json;
     }
 
diff --git a/src/test/java/hibernateTest/models/NativeApiIllustrationTest.java b/src/test/java/hibernateTest/models/NativeApiIllustrationTest.java
index c997103..50e4f9f 100644
--- a/src/test/java/hibernateTest/models/NativeApiIllustrationTest.java
+++ b/src/test/java/hibernateTest/models/NativeApiIllustrationTest.java
@@ -179,6 +179,7 @@
 		session = sessionFactory.openSession();
 		session.beginTransaction();
 		deleteRequest = (Request) session.load(Request.class, "005");//Banana cookie
+		System.out.println(deleteRequest.getUri());
 		//データの削除
 		if(deleteRequest != null){
 			session.delete(deleteRequest);