Reciprocating mechanism (6) for a fishing reel (100) for reciprocally moving a spool (4) with respect to a reel main body (2) so as to wind a fishing line onto the spool (4) equally and evenly. The reciprocating mechanism (6) includes a traverse camshaft (21) and an engaging unit (25). The traverse camshaft (21) includes a cam groove (21a) and rotates in conjunction with the winding operation of a handle (1) attached to the reel main body (2). The engaging unit (25) includes an engaging portion (25b) configured to engage the cam groove (21a). The engaging portion (25b) has a front end portion (128) extending in a direction along the cam groove (21a), the front end portion (128) being longer than a depth of the cam groove (21a).
