SHOCK ABSORBER

A shock absorber includes a cylinder, a piston, a piston rod, an expansion-side passage that allows a fluid to flow only from an expansion-side chamber toward a contraction-side chamber, a contraction-side passage that allows the fluid to flow only from the contraction-side chamber toward the expansion-side chamber, an expansion-side damping valve that applies resistance to a flow of fluid passing through the expansion-side passage, a contraction-side damping valve that applies resistance to a flow of fluid passing through the contraction-side passage, an expansion-side bypass passage that connects the expansion-side chamber to the contraction-side chamber, an expansion-side relief valve that is opened by pressure in the expansion-side chamber so as to open the expansion-side bypass passage, a contraction-side bypass passage that connects the expansion-side chamber to the contraction-side chamber, and a contraction-side relief valve that is opened by pressure in the contraction-side chamber so as to open the contraction-side bypass passage.