A vehicle door locking device Ao is integrated by assembling a base unit A2 provided with a latch mechanism A2a to a housing unit A1 provided with an actuating mechanism for actuating the latch mechanism A2a. A metal sub-base plate 27 of the base unit A2 has an attachment hole 27a fitted to a support shaft 11a provided in the housing unit A1 in the axial direction thereof, the support shaft extending in the vehicle length direction. The attachment hole 27a of the metal sub-base plate 27 is fitted to the support shaft 11a, so that the base unit A2 is integrated with the housing unit A1. The metal sub-base plate 27 is provided with a receiving portion 27b for restraining a lean in the vehicle width direction (W direction) of a child-proof lever 36 at a back part of the child-proof lever 36.