PURPOSE: To offset bending moment generated at a strut part by bending moment in the opposite direction generated at a sub oil cylinder by providing the sub oil cylinder on the car body outside of an oil cylinder so that it is in parallel with the oil cylinder.

CONSTITUTION: Oil chambers of an oil cylinder 1 and a pneumatic spring part 8 are communicated with each other. The bottom surface part of the oil cylinder 1 is connected to a supporting member 4 of a wheel 5, and the upper end part of a piston rod 3 to a member on the car body side respectively. In the above device, a sub oil cylinder 9 is provided between the supporting member 4 and the neighborhood of the upper end part of the piston rod 3 so that it is located further on the car body outside than the oil cylinder 1 and in parallel with it. An oil chamber of the sub oil cylinder 9 is communicated with the oil chamber of the oil cylinder 1 with a pipe 10. Thus, bending moment generated at strut parts 1 and 3 is offset by bending moment in the opposite direction generated at the sub oil cylinder.