A vehicle-height control system including a tank, a compressor, an actuator, and a valve between the tank and the compressor. The valve is closed to a state of a pressure medium supplier to the compressor-pressure supply state when a tank pressure has reached a threshold in a tank-pressure supply state in which the tank pressure is supplied to the actuator. In the compressor-pressure supply state, the tank pressure is kept at the threshold, and a pressure in the actuator is greater than the tank pressure. The threshold makes it difficult for a pressure differential in the valve to become greater than a valve-opening pressure differential, making it difficult for the valve to be opened in the compressor-pressure supply state. This system enables good supply of a pressure medium from the compressor to the actuator, avoiding a longer time for vehicle height control and achieving a shorter compressor operation time.