To increase the discharge of an air compressor in case of resetting car height to traveling time height from getting-on/off height without requiring an air tank of large capacity.

Air spring type suspension mechanism is provided with a car height sensor 5 for detecting the height of an air spring 9, an air compressor 14 that can switch air discharge rate, supplied to the air spring 9 via a car height adjusting valve 13, to at least two large-small stages, and an electronic control unit 6 for controlling the air compressor 14 and car height adjusting valve 13. In case of resetting car height to traveling time height from getting-on/off height, output of a motor is heightend by an output signal of the electronic control unit 6 based on a signal of a door switch 4 at the time of a getting-on/off door being closed, and the discharge rate of the air compressor 14 is switched to a large discharge state.