A shock absorber includes a damping force adjustment mechanism having a flow passage that allows the fluid from a cylinder, a valve seat, a valve body, and a stepper motor that adjusts a flow passage area by driving the valve body. A valve body position in which step-out may occur in the stepper motor if the valve body is moved further toward the valve seat therefrom is set as a step-out boundary position, a zone between a seated position in which the valve body is seated on the valve seat and the step-out boundary position is set as a step-out zone, and when the valve body is to be moved to the seated position through the step-out zone, the stepper motor is energized to move the valve body by a distance that is at least twice a distance to the seated position.