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).於釣魚用捲線器的往復移動機構中,可容易地將卡合構件安裝於滑動構件而不會降低滑動構件之強度。本擺動機構6包括導線凸輪軸21、卡合構件25及滑件本體24。導線凸輪軸21具有螺旋狀槽21a。導線凸輪軸21與安裝於捲線器本體2之搖柄1之捲取操作連動地轉動。卡合構件25具有可卡合於螺旋狀槽21a之卡合爪25b。滑件本體24具有可轉動地支持卡合構件25之支持孔部24f。於滑件本體24之支持孔部24f之內周面設置有沿支持孔部24f之貫通方向延伸的槽部24h。15‧‧‧捲線筒軸21‧‧‧導線凸輪軸21a‧‧‧螺旋狀槽(凸輪槽之一例)22‧‧‧滑件23‧‧‧中間齒輪24‧‧‧滑件本體(滑動構件之一例)24a‧‧‧捲線筒軸連結部24b‧‧‧卡合構件安裝部24c‧‧‧第1導引部24d‧‧‧第2導引部24f‧‧‧支持孔部24h‧‧‧槽部24m‧‧‧配置平面24n‧‧‧螺絲安裝部25‧‧‧卡合構件25a‧‧‧軸部(支持部之一例)25b‧‧‧卡合爪25e‧‧‧圓板部27‧‧‧防脫構件28‧‧‧螺絲構件29‧‧‧轉動支持部29a‧‧‧第1軸承29b‧‧‧第2軸承37‧‧‧螺絲構件38a‧‧‧第1導引軸38b‧‧‧第2導引軸39‧‧‧墊圈構件52‧‧‧減速機構53‧‧‧第1齒輪54‧‧‧第2齒輪55‧‧‧支持軸J1‧‧‧導線凸輪軸之軸線
