A dual-bearing reel includes a reel body, a drive shaft, a roller clutch, and a prevention member. The reel body includes a boss portion. The drive shaft extends through the boss portion and is rotatably supported in the reel body. The roller clutch includes an outer race non-rotatably mounted in the boss portion, an inner race connected to the drive shaft so as to be integrally rotatable, and a rolling element disposed between the outer race and the inner race. The roller clutch prevents rotation of the drive shaft in one direction. The prevention member is mounted on the outer perimeter of the boss portion to prevent radially outward expansion of the boss portion.[課題]即使在雙軸承捲線器捲線器本體的剛性較低的情況，也無關於捲線器本體的大小和剛性等可以採用小型且輕量的滾子離合器。 [技術內容]雙軸承捲線器(100)，是具備：捲線器本體(1)、及驅動軸(15)(軸構件的一例)、及滾子離合器(18)、及擴徑防止構件(5)。捲線器本體(1)，是具有轂部(9)。驅動軸(15)，是貫通轂部(9)，可旋轉地被支撐在捲線器本體(1)。滾子離合器(18)，是具有：不可旋轉地被裝設於轂部(9)的外輪(19)、與驅動軸(15)可一體旋轉地連結的內輪(20)、及被配置於外輪(19)及內輪(20)之間的轉動體(21)，禁止驅動軸(15)的一方向的旋轉。擴徑防止構件(5)，是被裝設於轂部(9)的外周，防止轂部(9)朝徑方向外側擴大。
