To enhance fluctuation-inhibiting effect on oil level in a hydraulic buffer which extends in approximately the horizontal direction.

In the hydraulic buffer, provided with an inner cylinder 3 in which a piston 5 is slidably housed, an outer cylinder 4 which partitions off a reservoir chamber 9 having partly a gas chamber to the outside of the inner cylinder 3, a suction port 14 which leads actuating hydraulic oil of the reservoir chamber 9 to the inside of the inner cylinder 3, and a discharge pipe 19 which leads the operating oil inside the inner cylinder 3 to the reservoir chamber 9, and in which a center line O of the inner cylinder 3 is arranged, so as to extend in approximately the horizontal direction, a tubular pipe 30, surrounding the inner cylinder 3, suction port 14 and the discharge pipe 19, for inhibiting oil level fluctuations is provided to the reservoir chamber 9.