PURPOSE: To alter the damping force of a shock absorber as the shock absorber attached to a vehicle is put to practical use as it is.

CONSTITUTION: A rod 11 having one end supported on the side of a front wheel 10 and the other end stretched toward a frame 1 is provided, and a shock absorber 14 having one end supported on the side of the front wheel 10 and the other end stretched toward the frame 1 is provided, and a lever 18 having the other end of the rod 11 supported at its one end and the other end of the shock absorber 14 supported at its other end and its middle serving as a rotating support is provided between the rod 11 and the other end of the shock absorber 14. A plurality of levers which are different in the ratio of a distance from the rotating support to the supporting point of the rod to a distance from the rotating support to the supporting point of the shock absorber are prepared as the lever 18, and the lever ratio is altered by exchanging the lever 18 to alter the function speed of the shork absorber 14 for altering its damping force.