diff --git a/packages/reactivity/src/collectionHandlers.ts b/packages/reactivity/src/collectionHandlers.ts
index f7ae9ae5dc6..93d09770c9a 100644
--- a/packages/reactivity/src/collectionHandlers.ts
+++ b/packages/reactivity/src/collectionHandlers.ts
@@ -21,7 +21,7 @@ const toReactive = <T extends unknown>(value: T): T =>
   isObject(value) ? reactive(value) : value
 
 const toReadonly = <T extends unknown>(value: T): T =>
-  isObject(value) ? readonly(value) : value
+  isObject(value) ? readonly(value as Record<any, any>) : value
 
 const toShallow = <T extends unknown>(value: T): T => value