1diff --git a/packages/core/types/index.d.ts b/packages/core/types/index.d.ts
2index ac44d69..889ef28 100644
3--- a/packages/core/types/index.d.ts
4+++ b/packages/core/types/index.d.ts
5@@ -26,7 +26,7 @@ interface MiddlewareAPI<D extends Dispatch = Dispatch, S = any> {
6 }
7
8 export interface Middleware<_DispatchExt = {}, S = any, D extends Dispatch = Dispatch> {
9- (api: MiddlewareAPI<D, S>): (next: (action: unknown) => unknown) => (action: unknown) => unknown
10+ (api: MiddlewareAPI<D, S>): (next: (action: AnyAction) => unknown) => (action: unknown) => unknown
11 }
12
13 /**
14diff --git a/packages/core/types/ts3.6/index.d.ts b/packages/core/types/ts3.6/index.d.ts
15index 3f4e107..d00b9d9 100644
16--- a/packages/core/types/ts3.6/index.d.ts
17+++ b/packages/core/types/ts3.6/index.d.ts
18@@ -25,7 +25,7 @@ interface MiddlewareAPI<D extends Dispatch = Dispatch, S = any> {
19 }
20
21 export interface Middleware<_DispatchExt = {}, S = any, D extends Dispatch = Dispatch> {
22- (api: MiddlewareAPI<D, S>): (next: (action: unknown) => unknown) => (action: unknown) => unknown
23+ (api: MiddlewareAPI<D, S>): (next: (action: AnyAction) => unknown) => (action: unknown) => unknown
24 }
25
26 /**