A shock absorber interposed in parallel with a suspension spring between a vehicle wheel and a vehicle body of a vehicle comprises a main piston (2) partitioning a cylinder (1) into a first operating chamber (R1) and a second operating chamber (R2), and connected to a piston rod (8). The first operating chamber (R1) and the second operating chamber (R2) are connected by a laminated leaf valve (V1, V2) under a first flow resistance. A passage (4a) connects one of the pressure chambers (R3A, R3B) partitioned by a free piston (5) and the first operating chamber (R1) under a second flow resistance. A passage (4b) connects the other of the pressure chambers (R3A, R3B) and the second operating chamber (R2) under a third flow resistance. The shock absorber displays stable damping force characteristics as a result of a spring (S) supporting the free piston (5) in a predetermined neutral position.