To make it possible to accurately discriminate the height of a driver's seat in a vehicle as compared with a case using a conventional sensor or the like by discriminating the height of the driver's seat based on a picture of a prescribed vehicle feature part processed and extracted by a picture processing means.

When a vehicle detector 1 detects a vehicle entered, a CCD camera 2 is driven to take a picture of the front part of the vehicle entered. A vehicle discrimination part 3 erases a background from the photographed picture, extracts only the image part of the vehicle entered, discriminates the position of a front glass, concretely the height of the lower edge of the front glass, from the extracted picture, and outputs a signal indicating the height. Since also the height of an window of a door on the driver's seat side is almost the same height as that of the front glass, a suitable position of a ticket issue port becomes a position slightly higher than the height of the lower edge of the front glass. Consequently which height of a ticket issue port is suitable for ejecting a parking ticket can be judged based on the height of the lower edge of the front glass.