To enable a desired vehicle height adjustment, without increasing the whole size, reducing consumption energy and product cost.

A pressure oil supply and discharge means 20 connected to a hydraulic jack 10 connected to an upper end of a suspension spring S locking a vehicle body B side of a vehicle by the upper end, while carrying a lower end to an axle side of the vehicle. The pressure oil supply and discharge means 20 has a driving source 22 constituted of an electric motor held on one end side in a case 21 formed into a cylindrical shape, a piston body 25 stored slidably in an axis direction of the case 21 on the other end side in the case 21 to partition an oil chamber R communicated with the hydraulic jack 10 and a gas chamber G provided with repulsive force by filled gas pressure, a threaded shaft part 24b for sliding the piston body 25 in the case 21 when driving the driving source 22, and an output means 24 constituted of a threaded hole to screw the threaded shaft part 24b. The piston body 25 is slid in the case 21 by driving the driving source 22 to supply pressure oil from the oil chamber R to the hydraulic jack 10. The pressure oil from the hydraulic jack 10 is stored in the oil chamber R.