A shock absorber includes a seal member that is slidably in contact with a piston rod, a friction member that is formed of an annular elastic rubber section slidably in contact with the piston rod and an annular base section to which the elastic rubber section is fixed, and an communication path that reduces pressure difference between both sides of the friction member in axial direction. The elastic rubber section is provided with a minimum inner diameter section, a first enlarged diameter section, and a second enlarged diameter section. A force is applied to the piston rod by the friction member such that movement in an outward direction of the cylinder becomes difficult and movement in an inward direction of the cylinder becomes easy.