A retainer member has a retainer portion, a through hole, and non-circular cross section. A bearing section is disposed on an outer periphery of the retainer portion. The through hole has a circular axial cross section and an inner periphery, which is axially penetrated by a non-circular portion of a spool shaft from back to front. The non-circular cross-sectional portion is formed by cutting out a front end of the retainer portion by machining. The non-circular cross-sectional portion has a non-circular axial cross section that engages the non-circular portion of the spool shaft.