diff --git a/fog.js b/fog.js
index 7e9d0a6..1a10b0a 100644
--- a/fog.js
+++ b/fog.js
@@ -14,8 +14,8 @@
     let playerMarker;
     let watchId = null;
 
-    // 解除済みエリア
-    const revealedLayers = L.layerGroup();
+    let fogLayer = null;
+    const revealedHoles = [];
 
     function initMap() {
       map = L.map("locationmap", { tap: true })
@@ -26,27 +26,56 @@
           '&copy; <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
       }).addTo(map);
 
-      revealedLayers.addTo(map);
-
       playerMarker = L.marker(map.getCenter()).addTo(map);
       playerMarker.bindPopup("STARTを押して探索開始").openPopup();
 
-      // PC検証用：クリックで移動
+      createFogLayer();
+
+      // PC検証用
       map.on("click", (e) => {
         updateLocation(e.latlng);
       });
     }
 
-    function revealFog(latlng) {
-      const circle = L.circle(latlng, {
-        radius: FOG_RADIUS,
-        color: "#4fc3f7",
-        fillColor: "#4fc3f7",
-        fillOpacity: 0.4,
-        weight: 1
-      });
+    // 世界全体を覆う霧を作る
+    function createFogLayer() {
+      const world = [
+        [-90, -180],
+        [-90,  180],
+        [ 90,  180],
+        [ 90, -180]
+      ];
 
-      revealedLayers.addLayer(circle);
+      fogLayer = L.polygon(
+        [world, ...revealedHoles],
+        {
+          color: "#000",
+          fillColor: "#000",
+          fillOpacity: 0.85,
+          weight: 0
+        }
+      ).addTo(map);
+    }
+
+    function revealFog(latlng) {
+      const points = [];
+      const steps = 24;
+
+      for (let i = 0; i < steps; i++) {
+        const angle = (i / steps) * Math.PI * 2;
+        const dx = (FOG_RADIUS / 111320) * Math.cos(angle);
+        const dy = (FOG_RADIUS / 111320) * Math.sin(angle);
+
+        points.push([
+          latlng.lat + dy,
+          latlng.lng + dx
+        ]);
+      }
+
+      revealedHoles.push(points);
+
+      map.removeLayer(fogLayer);
+      createFogLayer();
     }
 
     function updateLocation(latlng) {
@@ -56,7 +85,7 @@
       revealFog(latlng);
 
       playerMarker
-        .setPopupContent("探索中… 霧を解除しています")
+        .setPopupContent("探索中…霧を解除しています")
         .openPopup();
     }