A vehicle height adjusting device capable of kneeling without exhausting air in air springs into the atmosphere. It is possible to perform the kneeling in addition to a forward inclination without using supporting legs, a specific pump, and a moving device, as well as a disengaging device therefor. Furthermore, in order to avoid using the aforesaid moving device, kneeling circuits including an air reservoir device are provided, and when kneeling, the air inside the respective air springs is moved to and stored in the air reservoir device. As a result, the front part or the whole of the vehicle body is caused to kneel, while when returning from the kneeling state, the air stored in the air reservoir device is returned to the respective air springs by virtue of hydraulic pressure from a hydraulic source via the kneeling circuits. The entire vehicle body is returned to its original state with a normal air suspension state that is controlled by leveling valves.