To improve workability in assembling while enabling the predetermined damping action.

A piston side chamber R2 defined in an inner cylinder 1 by a piston body 3 can be communicated via a base valve part 5 arranged in the inner cylinder 1 with a reservoir R defined between an outer cylinder 4 arranged outside the inner cylinder 1 and itself, and the head side end of the outer cylinder 4 and the inner cylinder 1 is blocked up by a head member 6 for penetrating a rod body 2 having the tip side inserted into the inner cylinder 1 through an axial part, and the bottom side end of the outer cylinder 4 and the inner cylinder 1 is blocked up by a bottom member 8 for stabilizing the base valve part 5. The inner cylinder 1 threadably attaches a head side end part to the head member 6, and threadably attaches a bottom side end part to the bottom member 8. The outer cylinder 4 adjoins the head side end part to the head member 6 under arrangement of a seal member 6f, and adjoins the bottom side end part to the bottom member 8 under arrangement of a seal member 41a. The bottom side end part 4b in the outer cylinder 4 is connected to the bottom member 8 under arrangement of a fixing means 42.