An object of the present invention is to facilitate discharge of foreign matter present around a valve member, while inhibiting degradation of seal performance of the valve member. A shock absorber includes a cylinder portion containing a liquid, a piston valve partitioning a space in the cylinder portion into a first oil chamber and a second oil chamber which contain oil, a piston rod connected to the piston valve and moving in an axial direction of the cylinder portion, a piston nut 43 (cylinder portion 433) forming a channel for the liquid between the first oil chamber and the second oil chamber, and a float valve 52 deformed or displaced depending on the pressure of oil in the channel in the piston nut 43 to open and close the channel. The float valve 52 for the channel member includes a projecting portion 52P and a recessed portion 52M so that, with the position of the float valve 52 adjusted, a gap is formed between the float valve 52 and the piston nut 43 (cylinder portion 433).