diff --git a/src/app.ts b/src/app.ts
index a5e1ef3..06bb29b 100644
--- a/src/app.ts
+++ b/src/app.ts
@@ -3,6 +3,7 @@ import { BitGrid, BitWorld } from "@ca-ts/algo/bit";
 import { $autoRandom } from "./bind";
 import { createTemplateCell } from "./lib/cell";
 import { setRLE } from "./lib/setRLE";
+import { randomId } from "./lib/randomId";
 
 const stackHeight = 1;
 
@@ -80,7 +81,7 @@ export class App {
         // セルのインスタンスを作成
         const instance =
           this.meshPool.pop() ??
-          this.templateMesh.createInstance(`cell_${crypto.randomUUID()}`);
+          this.templateMesh.createInstance(`cell_${randomId()}`);
         instance.isVisible = true;
         instance.position = new BABYLON.Vector3(
           x,
diff --git a/src/lib/randomId.ts b/src/lib/randomId.ts
new file mode 100644
index 0000000..0ea9ef0
--- /dev/null
+++ b/src/lib/randomId.ts
@@ -0,0 +1,4 @@
+export function randomId() {
+  // httpで使用できない場合
+  return crypto.randomUUID ? crypto.randomUUID() : Math.random().toString(16);
+}