A shock absorber includes a cylinder in which oil is sealed, a piston slidably fitted into the cylinder, a piston rod connected to the piston and extending to the outside of the cylinder, and a damping force generating apparatus controlling a flow of the oil generated by the sliding of the piston inside the cylinder. The damping force generating apparatus includes a valve body generating a damping force by being opened and closed on a flow path in which the oil flows, a valve seat closing the flow path when the valve body is seated, and an actuator generating thrust to the valve body in a valve closing direction. The valve seat has a first elastic body which is elastically deformable in the valve closing direction of the valve body.