A vehicle door latch device which prevents a theft component from getting into an operation-mechanism holding portion thereby improving an anti-theft performance of the vehicle door latch device, by a smaller and lighter arrangement. On a synthetic-resin body, a protection wall is provided that prevents a theft component, inserted in the door, from getting into the casing by covering a connecting part of an outside lever and an operation mechanism, held in the casing, from a vehicle-outside direction.