Abstract: A cylinder 3 is fitted with a piston 5. A pump rod 12 is fitted into a pump tube 11 in a piston rod 6 to form a pump chamber 13. An oil tank 17 is connected to the pump chamber 13 by a line 16 through a switching valve mechanism 18. An accumulator tank 20 is connected to the cylinder 3 by a line 19 through a switching valve 21. Normally, the switching valve 21 is closed, and a switching valve 26 is set to a position (a) in which the fluid flows to the pump chamber through a check value 27. By using the pump chamber 13 and check valves 23 and 27, a hydraulic fluid is supplied from the oil tank 17 to the accumulator tank 20 by the extension and contraction of the piston rod 6, thereby accumulating the pressurized hydraulic fluid in the accumulator tank 20. By opening the switching valve 21, the cylinder 3 is pressurized to raise the vehicle height.