diff --git a/src/reactivity.ts b/src/reactivity.ts
index 86aede0d..a4a63b54 100644
--- a/src/reactivity.ts
+++ b/src/reactivity.ts
@@ -207,7 +207,7 @@ export function reactive<T extends Target>(
     return reactive(originalTarget, callback);
   }
   if (!reactiveCache.has(target)) {
-    reactiveCache.set(target, new Map());
+    reactiveCache.set(target, new WeakMap());
   }
   const reactivesForTarget = reactiveCache.get(target)!;
   if (!reactivesForTarget.has(callback)) {