To surely prevent the opening of a trunk and an indoor box for a car by a third person without delivering a special key to the third person when a driver entrusts the car to the third person.

A luggage-box locking device has a normal mode and a valley mode as control modes for a computer 30. The release of the locked states of the trunk and the indoor box is permitted in the normal mode. The release of the locked states of the trunk and the indoor box are inhibited in the valley mode. When the driver entrusts the car to the third person, the third person cannot open the trunk and the indoor box by changing over a mode from the normal mode to the valley mode. When the car is returned from the third person to the driver, the mode can be changed over from the valley mode to the normal mode by confirming whether or not an authetication information input to an authentication input section by the driver and a registration information have a specified corresponding relationship. The trunk and the indoor box can be opened normally.