PURPOSE: To improve riding comfortability on a vehicle, reduce or restrain generation of roll steer, and improve operation stability.

CONSTITUTION: A pair of trailing arms 10 of which the front ends are pivotally supported with a body through a bush device 14 and wheels are rotatably supported with the rear end, are provided. The bush device comprises an outer cylinder 38 fixed with the front end of the arm 10 and one side of a body, an inner cylinder 40 fixed with the front end and the other side of the body, an upper part rubber-like elastic body 42 of which the lower end is fixed with the inner cylinder and the upper end is fixed with the inner cylinder, and a lower part rubber-like elastic body 44 of which the upper end is fixed with the inner cylinder and the lower end is fixed with the outer cylinder. The lower part rubber-like elastic body has higher flexural rigidity in the front and rear direction than that of the upper part rubber-like elastic body.