diff --git a/map/game/game.js b/map/game/game.js
index 1c7dfa9..0477796 100644
--- a/map/game/game.js
+++ b/map/game/game.js
@@ -27,11 +27,10 @@
 	info.innerHTML = '距離: '+Math.round(totalDist*100)/100+'m';
     }
     
-    function stopGPS() {
+    function stopGPS() {	// watchが動いていたら止めてnullにする
 	console.log("watchId="+watchId);
-	if (watchId != null) {
+	if (watchId != null) {	// nullかどうかで比較しないとだめ(初期値0)
 	    navigator.geolocation.clearWatch(watchId);
-	    document.getElementById("title").textContent = "stop";
 	    gpsmarker.setPopupContent("停めました");
 	}
 	watchId = null;
@@ -41,7 +40,6 @@
 	watchId = navigator.geolocation.watchPosition(
 	    onSuccess, onError,{
 		maximumAge: 0, timeout: 3000, enableHighAccuracy: true});
-	document.getElementById("title").textContent = "START";
     }
     function onSuccess(pos) {
 	var latlng = L.latLng([pos.coords.latitude, pos.coords.longitude]);