PURPOSE: To adjust the initial setting load of a suspension spring freely by providing a cam cylinder between a holder that holes one end of a suspension spring and a stopper that is projected from a shock absorber proper.

CONSTITUTION: A piston rod 2 is slidably inserted into a shock absorber proper 1, a suspension spring 7 is provided between the shock absorber 1 and the piston rod 2 through holders 5, 6. Also a guide cylinder 8 is installed on the outer circumference of the absorber proper 1. A cam cylinder 12 is put onto the guide cylinder 8 so that it is relatively rotatable on the guide cylinder 8, the cam faces 13, 14 are formed on the upper and lower end faces of the cam cylinder 12. The cam face 13 is formed at a fixed height so that it is allowed to turn only in a fixed direction when the projection 5a of the holder 5 matches with the cam face 13, the cam face 14 is formed so that it has step faces 14aW14d the heights of which are gradually different from each other and it is allowed to turn only in one direction when the stopper 10 matches with the cam face 14.