diff --git a/roles/host.py b/roles/host.py
index 400fce4d85ebfa1cc23b314d97efcf3c3a498bdb..73a9d98cdd0ddae5aa1e12e423481db3461010af 100644
--- a/roles/host.py
+++ b/roles/host.py
@@ -125,6 +125,9 @@ class Host(object):
         elif cmd == 'request/status':
             request_id = float(params['request_id'])
             return self.get_request_status(request_id)
+        elif cmd == 'stop':
+            self.worker_manager.request_stop()
+            return {}
         elif cmd == 'view/solution':
             problem_key = params['problem']
             solution_id = params['solution']
@@ -150,6 +153,9 @@ class WorkerManager(object):
     def get_workers(self):
         return self.workers
 
+    def request_stop(self):
+        self.broadcast('stop', {})
+
     def broadcast(self, cmd, params):
 
         threads = []
diff --git a/roles/solver.py b/roles/solver.py
index f79096b5fda83f8f053b5a2e522f8abdfd437d3d..8668abda64390c02f3792a42b94c7eeeae090d91 100644
--- a/roles/solver.py
+++ b/roles/solver.py
@@ -12,7 +12,7 @@ class StoppableThread(threading.Thread):
         super(StoppableThread, self).__init__(target=target, args=args)
         self._status = 'running'
     def stop(self):
-        if self._status == 'running':
+        if self.is_running():
             self._status = 'stopping'
     def stopped(self):
         self._status = 'stopped'
@@ -80,18 +80,22 @@ class Solver(object):
         else:
             return {'status': 'busy'}
         
-    def stop_solver():
+    def stop_solver(self):
 
         if self.thread is not None:
             if self.thread.is_running():
                 self.thread.stop()
-                self.thread.join()
+                self.thread.join(0.1)
                 self.thread = None
+        
+        return {'status': 'stopped'}
 
     def call_api(self, method, cmd, params):
         if cmd == 'role':
             return {'role': self.type}
         elif cmd == 'solve':
             return self.start_solver(params)
+        elif cmd == 'stop':
+            return self.stop_solver()
         else:
             return None
diff --git a/static/js/adc2019.js b/static/js/adc2019.js
index 171cbb231e7ec9a92b7fa835b4b3e57f2376b567..72d16c66c5d354da644ca149c48c847f5708e4f6 100644
--- a/static/js/adc2019.js
+++ b/static/js/adc2019.js
@@ -49,7 +49,6 @@ class StatusView {
             }),
             contentType: 'application/json'
         }).done((d) => {
-            // TODO: タイムアウトになる時間まで，モーダル表示させる
             var request_id = d['request_id'];
             var timeout = d['timeout'];
 
@@ -62,10 +61,28 @@ class StatusView {
                 // console.log(e);
                 _this.show_problem();
             })
+            
+            _this.container.find('.stop-button').click(()=>{
+                _this.stop_solver();
+            });
 
             _this.get_request_status(request_id, timeout);
         });
     }
+    
+    // 強制停止
+    stop_solver(){
+        var _this = this;
+        
+        $.ajax({
+            type: "GET",
+            dataType: "json",
+            url: "/api/stop",
+        }).done((d) => {
+            _this.request_refresh_timer = 'stopped';
+            alert(d);
+        });
+    }
 
     get_request_status(request_id, timeout){
         var _this = this;
@@ -81,6 +98,8 @@ class StatusView {
             // console.log(status);
             if(status == 'done'){
                 _this.request_refresh_timer = null;
+            }else if(_this.request_refresh_timer == 'stopped'){
+                _this.request_refresh_timer = null;
             }else{
                 _this.request_refresh_timer = setTimeout(_this.get_request_status(request_id, timeout), 1000);
             }
diff --git a/templates/part_problem_status.html b/templates/part_problem_status.html
index 088a64e77df5c8fa891f67476fe7d56de9daf24d..e3565ac799b766854ccc5ea5b8522969d6b5e6fc 100644
--- a/templates/part_problem_status.html
+++ b/templates/part_problem_status.html
@@ -55,7 +55,7 @@
             処理中...
             </div>
             <div class="modal-footer">
-                <button type="button" class="btn btn-danger">Stop</button>
+                <button type="button" class="btn btn-danger stop-button">Stop</button>
                 <button type="button" class="btn btn-primary" data-dismiss="modal">Close</button>
             </div>
         </div>