A vehicle height adjustment apparatus comprising: a plurality of vehicle height adjustment units that are respectively provided to correspond to wheels of a vehicle body, and adjust a vehicle height in response to the supply and discharge of a working fluid; a supply source of the working fluid; a plurality of opening and closing valves that are interposed between the vehicle height adjustment units and the supply source; and a control unit that adjusts a vehicle height for each of the vehicle height adjustment units to at least one of a first vehicle height suitable for at least one of boarding and deboarding, and a second vehicle height suitable for travelling, wherein when the control unit acquires preparation information indicative of the transition of a preparation state to at least one of a boarding preparation state and a deboarding preparation state, the control unit adjusts the vehicle height adjustment units from the second vehicle height to the first vehicle height, wherein the supply source includes a pressure tank that stores the working fluid, and a compressor that pressure-feeds the working fluid, characterized in that the plurality of opening and closing valves includes first and second opening and closing valves (24a, 24b), a first end of each of which is connected to the pressure tank via a tank connection main flow passage; a third opening and closing valve, a first end of which is connected to an outlet of the compressor via a compressor outlet flow passage and a second end of the second opening and closing valve, and a second end of which is connected to the vehicle height adjustment unit; and a fourth opening and closing valve, a first end of which is connected to an inlet of the compressor via a compressor inlet flow passage and a second end of the first opening and closing valve, and a second end of which is connected to the vehicle height adjustment unit, and when the working fluid flows from the pressure tank to the vehicle height adjustment unit due to a pressure difference there between, the control unit selects at least one of a first flow passage system that is formed when the first and fourth opening and closing valves (24a, 24d) are opened, and a second flow passage system that is formed when the second and third opening and closing valves (24b, 24c) are opened. a plurality of vehicle height adjustment units that are respectively provided to correspond to wheels of a vehicle body, and adjust a vehicle height in response to the supply and discharge of a working fluid; a supply source of the working fluid; a plurality of opening and closing valves that are interposed between the vehicle height adjustment units and the supply source; and a control unit that adjusts a vehicle height for each of the vehicle height adjustment units to at least one of a first vehicle height suitable for at least one of boarding and deboarding, and a second vehicle height suitable for travelling, wherein when the control unit acquires preparation information indicative of the transition of a preparation state to at least one of a boarding preparation state and a deboarding preparation state, the control unit adjusts the vehicle height adjustment units from the second vehicle height to the first vehicle height, wherein the supply source includes a pressure tank that stores the working fluid, and a compressor that pressure-feeds the working fluid, characterized in that the plurality of opening and closing valves includes first and second opening and closing valves (24a, 24b), a first end of each of which is connected to the pressure tank via a tank connection main flow passage; a third opening and closing valve, a first end of which is connected to an outlet of the compressor via a compressor outlet flow passage and a second end of the second opening and closing valve, and a second end of which is connected to the vehicle height adjustment unit; and a fourth opening and closing valve, a first end of which is connected to an inlet of the compressor via a compressor inlet flow passage and a second end of the first opening and closing valve, and a second end of which is connected to the vehicle height adjustment unit, and when the working fluid flows from the pressure tank to the vehicle height adjustment unit due to a pressure difference there between, the control unit selects at least one of a first flow passage system that is formed when the first and fourth opening and closing valves (24a, 24d) are opened, and a second flow passage system that is formed when the second and third opening and closing valves (24b, 24c) are opened.