Abstract: The invention is directed to provide a shock absorber in which hydraulic fluid is restrained from leaking out from a gap between a sub-check valve provided at a passage opening of an orifice passage and a disc valve. The sub-check valve (133) is biased toward the opening (126) of the orifice passage (130) using a biasing disc (135) (biasing member) of substantially equal diameter to the sub-check valve (133). This makes it possible to restrain hydraulic fluid in a first chamber (2A) from leaking out from a gap between a disc valve (121) and the sub-check valve (133) into a second chamber (2B) when piston velocity during an extension stroke is low (0.1 m/s or lower, exclusive zero), and thus obtain an intended damping force.

Abstract: A shock absorber is configured in such a manner that a flow passage area of each of first orifices 169 and 189 is smallest throughout a communication passage that establishes communication between a chamber 2A or 2B on an upstream side and a chamber 2B or 2A on a downstream side, and therefore prevents a pressure in a back-pressure chamber 55 or 26 from excessively increasing. As a result, the shock absorber can prevent overshoot of a damping force due to a delay of valve opening of a main valve 53 or 23 due to a remaining pressure in the back-pressure chamber 55 or 26 when a movement of a piston 3 is switched from one direction to an opposite direction.