To temporarily change previously set damping force following to change of the running condition by directly or indirectly abutting to a plurality of abutting parts of a regulating rod, and enabling the opening area of a bypass flow passage to be regulated by means of a plurality of adjusters advancing/ retreating the regulating rod in the axial direction.

A first adjuster 51 is provided on a fitting member 15 fixed to the outer end part of a piston rod 12, it is rotated by a rotation operating tool to be threadely moved, and a regulating rod 43 can be advanced/retreated in the axial direction by displacement of a cam face. A second adjuster 61 is provided on the fitting member 15, and can advance or retreat the regulating rod 43 in the axial direction. At this time, the second adjuster 61 is set to push the needle valve 43A of the regulating rod 43 into a restricted position, and reference damping force previously set by the first adjuster 51 can be temporarily changed. Hereby, the previously set damping force can be temporarily changed following to change of the running condition.