To inexpensively control turning-on of illumination in a parking space of a parking garage with a serviceable constitution.

This parking garage device has an illuminating means 2 for illuminating the parking space S of one vehicle, a light reflecting means 10 arranged in a position for intercepting the light from the illuminating means 2 by the vehicle C parked in the parking space S, a detecting means 4 of the reflected light from the light reflecting means 10, and a turning-off means 6 for turning off illumination of the illuminating means 2 when being unable to detect the reflected light in the detecting means 4.