Abstract: An oscillating mechanism is for reciprocating a spool in a spool shaft direction in cooperation with rotation of a handle. The oscillating mechanism includes a slider member, a gear member, and a guide shaft. The slider member is mounted at least axially immovably to a spool shaft, on the fore end of which the spool is mounted. The gear member reciprocates the slider member in the shaft axial direction in cooperation with rotation of the handle. The guide shaft is supported at two locations of its outer circumferential surface with the reel unit, has an annular groove to which a retainer can be attached for preventing disengagement of the guide shaft in one axial direction, and guides the slider member in a direction substantially parallel to the spool shaft. In this way, structure for retaining a guide shaft is simplified and design constraint alleviated.