diff --git a/types/index.d.ts b/types/index.d.ts
index 6d5bf8f..6b431db 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -253,7 +253,7 @@ export interface WorkBook {
     Props?: FullProperties;
 
     /** Custom workbook Properties */
-    Custprops?: object;
+    Custprops?: any;
 
     Workbook?: WBProps;