diff --git a/app/src/main/java/org/ntlab/irisclient/CreateRoomActivity.java b/app/src/main/java/org/ntlab/irisclient/CreateRoomActivity.java
index e4d7429..8354a6f 100644
--- a/app/src/main/java/org/ntlab/irisclient/CreateRoomActivity.java
+++ b/app/src/main/java/org/ntlab/irisclient/CreateRoomActivity.java
@@ -14,6 +14,7 @@
 import android.widget.Button;
 import android.widget.ImageButton;
 import android.app.AlertDialog;
+import android.widget.EditText;
 
 public class CreateRoomActivity extends AppCompatActivity {
 
@@ -29,10 +30,10 @@
             actionBar.hide();
         }
 //------------------------------------------------------------------------------------------------------------------------------------------
-        //前の画面に遷移
+        //バックボタンを押した場合、前の画面に遷移
         Intent intent = getIntent();
 
-        ImageButton imageButton = (ImageButton) findViewById(R.id.imageButton); // view経由でimageButtonを探す
+        ImageButton imageButton = (ImageButton) findViewById(R.id.backButton); // view経由でimageButtonを探す
         imageButton.setOnClickListener(new View.OnClickListener() {
             public void onClick(View v) {
                 Intent i = new Intent(v.getContext(), MainActivity.class);
@@ -40,46 +41,27 @@
             }
         });
 
-/*-------------------------------------------------------------------------------------------------------------------------------------------
-        public boolean onCreateOptionsMenu(Menu menu) {
-            // Inflate the menu; this adds items to the action bar if it is present.
-            getMenuInflater().inflate(R.menu.main, menu);
-            return true;
-        }
+//-------------------------------------------------------------------------------------------------------------------------------------------
 
-        public void CreateRoomButton(View view){
-            AlertDialog.Builder builder = new AlertDialog.Builder(this);
-            builder.setMessage("ニックネームを入力してください");
-            builder.setPositiveButton("確認", new DialogInterface.OnClickListener() {
-
-                AlertDialog dialog = builder.create();
-            dialog.show();
-            });
-        }
-
-------------------------------------------------------------------------------------------------------------------------------------------*/
-        //部屋を作る次の画面に遷移
+        //ボタンをクリックすると、部屋を作る次の画面に遷移
         Button nextButton = findViewById(R.id.CreateRoomButton);
+        EditText text = (EditText) findViewById(R.id.nicknameEditText);
         nextButton.setOnClickListener(new View.OnClickListener() {
             public void onClick(View v) {
-                Intent i = new Intent(getApplication(), MainActivity/*OwnerActivityに変更する*/.class);
-                startActivity(i);
+
+                //ニックネームが入力されていない場合エラーメッセージを表示する
+                if (text.getText().toString().isEmpty()) {
+                    text.setError("ニックネームを入力されていません");
+
+                //ニックネームが入力されていれば次の画面へ
+                } else {
+                    Intent i = new Intent(getApplication(), MainActivity/*OwnerRoomActivityに変更する*/.class);
+                    startActivity(i);
+                }
+
             }
         });
 
     }
-
-
-//       public void onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
-//        View view = inflater.inflate(R.layout.activity_create_room, container, false);
-//        ImageButton imageButton = (ImageButton) view.findViewById(R.id.imageButton); // view経由でimageButtonを探す
-//        imageButton.setOnClickListener(new View.OnClickListener() {
-//            public void onClick(View v) {
-//                Intent i = new Intent(v.getContext(), MainActivity.class);
-//                startActivity(i);
-//            }
-//        });
-//    }
-
-
 }
+