diff --git a/dist/types/backlog.d.ts b/dist/types/backlog.d.ts
index 112ab30..8eb7d7c 100644
--- a/dist/types/backlog.d.ts
+++ b/dist/types/backlog.d.ts
@@ -550,7 +550,7 @@ export default class Backlog extends Request {
     /**
      * https://developer.nulab.com/docs/backlog/api/2/add-watching
      */
-    postWatchingListItem(params: any): Promise<Entity.WatchingList.WatchingListItem>;
+    postWatchingListItem(params: Option.WatchingList.PostWatchingListItemParams): Promise<Entity.WatchingList.WatchingListItem>;
     /**
      * https://developer.nulab.com/docs/backlog/api/2/update-watching
      */
@@ -572,7 +572,7 @@ export default class Backlog extends Request {
      * https://developer.nulab.com/docs/backlog/api/2/add-project-group
      * @deprecated
      */
-    postProjectGroup(projectIdOrKey: string | number, params: any): Promise<Entity.Group.Group>;
+    postProjectGroup(projectIdOrKey: string | number, params: Option.Group.PostProjectGroupParams): Promise<Entity.Group.Group>;
     /**
      * https://developer.nulab.com/docs/backlog/api/2/delete-project-group
      * @deprecated
diff --git a/dist/types/option.d.ts b/dist/types/option.d.ts
index 65d5fb2..9b8974c 100644
--- a/dist/types/option.d.ts
+++ b/dist/types/option.d.ts
@@ -61,20 +61,41 @@ export declare namespace User {
         count?: number;
     }
 }
+export declare namespace WatchingList {
+    interface PostWatchingListItemParams {
+        issueIdOrKey: string | number;
+        note: string;
+    }
+}
 export declare namespace Group {
+    /**
+     * @deprecated
+     */
     interface GetGroupsParams {
         order?: Order;
         offset?: number;
         count?: number;
     }
+    /**
+     * @deprecated
+     */
     interface PostGroupsParams {
         name: string;
         members?: string[];
     }
+    /**
+     * @deprecated
+     */
     interface PatchGroupParams {
         name?: string;
         members?: string[];
     }
+    /**
+     * @deprecated
+     */
+    interface PostProjectGroupParams {
+        groupId: number;
+    }
 }
 export declare namespace Team {
     interface GetTeamsParams {
diff --git a/src/backlog.ts b/src/backlog.ts
index 1d48883..1e27cb8 100644
--- a/src/backlog.ts
+++ b/src/backlog.ts
@@ -1109,7 +1109,9 @@ export default class Backlog extends Request {
   /**
    * https://developer.nulab.com/docs/backlog/api/2/add-watching
    */
-  public postWatchingListItem(params: any): Promise<Entity.WatchingList.WatchingListItem> {
+  public postWatchingListItem(
+    params: Option.WatchingList.PostWatchingListItemParams,
+  ): Promise<Entity.WatchingList.WatchingListItem> {
     return this.post(`watchings`, params);
   }
 
@@ -1147,7 +1149,10 @@ export default class Backlog extends Request {
    * https://developer.nulab.com/docs/backlog/api/2/add-project-group
    * @deprecated
    */
-  public postProjectGroup(projectIdOrKey: string | number, params: any): Promise<Entity.Group.Group> {
+  public postProjectGroup(
+    projectIdOrKey: string | number,
+    params: Option.Group.PostProjectGroupParams,
+  ): Promise<Entity.Group.Group> {
     console.warn("Deprecated: Use postProjectTeam instead.");
     return this.post(`projects/${projectIdOrKey}/groups`, params);
   }
diff --git a/src/option.ts b/src/option.ts
index 7aa32a5..b58af1e 100644
--- a/src/option.ts
+++ b/src/option.ts
@@ -79,24 +79,45 @@
 
   }
 
-  export namespace Group {
+  export namespace WatchingList {
+    export interface PostWatchingListItemParams {
+      issueIdOrKey: string | number;
+      note: string;
+    }
+  }
 
+  export namespace Group {
+    /**
+     * @deprecated
+     */
     export interface GetGroupsParams {
       order?: Order;
       offset?: number;
       count?: number;
     }
 
+    /**
+     * @deprecated
+     */
     export interface PostGroupsParams {
       name: string;
       members?: string[];
     }
 
+    /**
+     * @deprecated
+     */
     export interface PatchGroupParams {
       name?: string;
       members?: string[];
     }
 
+    /**
+     * @deprecated
+     */
+    export interface PostProjectGroupParams {
+      groupId: number;
+    }
   }
 
   export namespace Team {