A shock absorber comprises a first passage (2a, 2b) and a second passage (15) connecting a first fluid chamber (41) and a second fluid chamber (42). A throttle (12, 14) narrows an inflow of fluid to the first passage (2a, 2b) according to an applied displacement pressure. The displacement pressure includes a fluid pressure in one of the two fluid chambers (41, 42) and a pressure that depends on a velocity of the fluid flow through the throttle (12, 14). A spring (25, 29) biases the throttle (12, 14) in the opposite direction to narrow the fluid flow. The second passage (15) comprises a pair of orifices (16a, 17a). By exerting a pressure between the pair of orifices (16a, 17a) on the throttle (12, 14) in the opposite direction to narrow the fluid flow, the spring load required of the spring (25, 29) is reduced.