A vehicle height adjustment device includes a changer, a detector, and a controller. The changer is configured to change a relative position of a body of a vehicle to an axle of a wheel of the vehicle. The detector is configured to detect the relative position. The controller is configured to control the changer to change the relative position based on a detection value detected by the detector so as to control a height of the body as a vehicle height. The controller is configured to control the changer to maintain the vehicle height when there is a possibility of a malfunction in the detector.