Abstract: An arrangement for locking a cover which can be opened and closed to cover an opening of a vehicle such as a door or luggage lid is disclosed. Means for detecting the presence or absence of an occupant within the vehicle as well as means for detecting the open or closed condition of the cover are provided. When the absence of an occupant is detected and the closed condition of the opening cover is detected, a lock mechanism which blocks an opening movement of the opening cover is locked. In this manner, if an occupant has forgotten to lock a door or doors when getting off his vehicle, the doors are automatically locked, thus reliably preventing a theft or tampering with the vehicle.