diff --git a/ISCamRecorder/MainForm.cs b/ISCamRecorder/MainForm.cs
index d54c1be..0a0103b 100644
--- a/ISCamRecorder/MainForm.cs
+++ b/ISCamRecorder/MainForm.cs
@@ -53,7 +53,7 @@
             _Cameras.ForEach(c => c.Connect());
 
             // タイマー起動
-            _UITimer = new System.Threading.Timer(UITimerCB, this, 0, 100);
+            _UITimer = new System.Threading.Timer(UITimerCB, this, 0, 30);
             _TriggerThread = Task.Run(TriggerThread);
             _SerialThread = Task.Run(SerialThread);
             _LastUpdate = DateTime.Now;
@@ -89,9 +89,12 @@
         /// </summary>
         private void Plot() {
             chart1.Series[0].Points.Clear();
-            var times = _Sensor.Times.ToList();
-            var values = _Sensor.Values.ToList();
-            chart1.Series[0].Points.DataBindXY(times, values);
+            lock (SensorData.Locker) {
+                //var times = _Sensor.Times.ToList();
+                //var values = _Sensor.Values.ToList();
+                //chart1.Series[0].Points.DataBindXY(times, values);
+                chart1.Series[0].Points.DataBindXY(_Sensor.Times, _Sensor.Values);
+            }
         }
 
 
diff --git a/ISCamRecorder/SensorData.cs b/ISCamRecorder/SensorData.cs
index 6b03439..29a58fd 100644
--- a/ISCamRecorder/SensorData.cs
+++ b/ISCamRecorder/SensorData.cs
@@ -16,6 +16,7 @@
         SerialPort _Serial = null;
         bool _ExitSignal = false;       // 終了シグナル
         int _QueueLength = 100;
+        public static object Locker = new object();
 
         /// <summary>
         /// 接続
@@ -61,11 +62,13 @@
                 var str = _Serial.ReadLine();
                 var val = int.Parse(str);
                 var dt = DateTime.Now;
-                Values.Enqueue(val);
-                Times.Enqueue(dt);
-                if (Values.Count > _QueueLength) {
-                    Values.Dequeue();
-                    Times.Dequeue();
+                lock (Locker) {
+                    Values.Enqueue(val);
+                    Times.Enqueue(dt);
+                    if (Values.Count > _QueueLength) {
+                        Values.Dequeue();
+                        Times.Dequeue();
+                    }
                 }
             }