diff --git a/src/main/java/com/ntlab/irisserver/entities/DrawingController.java b/src/main/java/com/ntlab/irisserver/entities/DrawingController.java
index 0ef55d2..fec47bd 100644
--- a/src/main/java/com/ntlab/irisserver/entities/DrawingController.java
+++ b/src/main/java/com/ntlab/irisserver/entities/DrawingController.java
@@ -64,8 +64,11 @@
 
     //pathパラメーターを引数にするので、memberではなくてString
     //nicknameから書いてほしいdnoを返す
-    public int getDno(String nickname) {
+    public Integer getDno(String nickname) {
         Member mem = membersMap.get(nickname);
+        if(mem == null){
+            return null;
+        }
         List<Integer> dnoList = assignments.get(mem);
         int dno = dnoList.get(stage);
         return dno;
diff --git a/src/main/java/com/ntlab/irisserver/resources/AssignmentRest.java b/src/main/java/com/ntlab/irisserver/resources/AssignmentRest.java
index 8a7c38f..93c5330 100644
--- a/src/main/java/com/ntlab/irisserver/resources/AssignmentRest.java
+++ b/src/main/java/com/ntlab/irisserver/resources/AssignmentRest.java
@@ -6,11 +6,9 @@
 import com.ntlab.irisserver.models.RoomManager;
 import org.springframework.stereotype.Component;
 
-import javax.ws.rs.GET;
-import javax.ws.rs.Path;
-import javax.ws.rs.PathParam;
-import javax.ws.rs.Produces;
+import javax.ws.rs.*;
 import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
 import java.util.List;
 
 @Component
@@ -22,13 +20,31 @@
     @Produces(MediaType.APPLICATION_JSON)
     public int getDno(@PathParam("rid") String rid,@PathParam("nickname") String nickname ) {
 
+        Integer dno = null;
+
         RoomManager rm = RoomManager.getInstance();
         Room room = rm.getRoom(rid);
-        Game game = room.getGame();
-        DrawingController drawingController = game.getDrawingController();
+        if(room != null) {
 
-        int dno = 0;
-        dno = drawingController.getDno(nickname);
+            Game game = room.getGame();
+            DrawingController drawingController = game.getDrawingController();
+            dno = drawingController.getDno(nickname);           // dno = new Integer(drawingController.getDno(nickname));
+
+            if(dno == null ){
+
+                //プレイヤーがいなければエラー
+                var response = Response.status(Response.Status.NO_CONTENT);
+                response.status(404).entity("プレイヤーが存在しません");
+                throw new WebApplicationException(response.build());
+            }
+
+        }else{
+            //部屋がなければエラー
+            var response = Response.status(Response.Status.NO_CONTENT);
+            response.status(404).entity("部屋が存在しません");
+            throw new WebApplicationException(response.build());
+        }
+
 
         return dno;
     }