In this shock absorber, a piston includes a first piston body, a second piston body, and a piston band. The first piston body includes a first passage, a second passage, a first seat, and a second seat. The first seat communicates with the first passage and on which a first damping valve is placed. A second damping valve is placed on the second seat. The second piston body includes a third passage, a fourth passage, a third seat, and a fourth seat. The third seat communicates with the fourth passage and on which a third damping valve is placed. A fourth damping valve is placed on the fourth seat.