A shock absorber includes a bearing unit having a bearing and a bearing holding member, and a seal unit having a seal member and a seal holding member. The seal holding member includes a seal accommodating portion being configured to accommodate the seal member, and an insertion hole through which a piston rod is inserted. The seal member is pressed against an outer circumferential surface of the piston rod and the seal accommodating portion by working-fluid pressure in the extension-side chamber. And the bearing is provided such that a first end surface of the bearing facing the seal member matches an aperture plane of a through hole of the bearing holding member or such that the first end surface of the bearing projects out from the aperture plane of the through hole.