A collar member is used for a spinning reel. The spinning reel has a reel body, a spool shaft that moves in a front-back direction with respect to the reel body, a pinion gear that rotates around the spool shaft, a rotor nut that rotates integrally with the pinion gear, and a bearing that is disposed between the spool shaft and the rotor nut in a radial direction and rotatably supports the rotor nut. The collar member is disposed between the spool shaft and the bearing in the radial direction. The collar member is formed by a resin material that has a linear expansion coefficient of 10×10−6 (1/° C.) or more and 50×10−6 (1/° C.) or less.