A vehicle height adjustment device includes a changer, a vehicle height controller, and a malfunction detector. The changer is configured to change a relative position of a body of a vehicle relative to an axle of a wheel of the vehicle. The vehicle height controller is configured to change the relative position based on a detection value detected by a detector configured to detect the relative position so as to control a vehicle height, which is a height of the body. The malfunction detector is configured to detect a malfunction in at least one of the changer and the detector, the malfunction causing the vehicle height controller to continue to control the vehicle height to increase.