A spool (4) for preventing backlash includes a bobbin trunk (7a) , a rear flange portion (18e), and a front flange portion (8). The front flange portion (8) includes a first protruding portion (17a) and a first oblique portion (17b) that protrudes upward and forward from a tip of the first protruding portion (17a). The rear flange portion (18e) includes a second protruding portion (18a) and a second oblique portion (18b) that protrudes upward and rearward from a tip of the second protruding portion (18a). A length (B) in the radial direction of the second protruding portion (18b) is approximately the same as a length (A) of the first protruding portion (17a).【課題】對於紡車式捲線器的捲筒上，可確實防止釣線；纏結。；【解決手段】捲筒(4)，是具有：捲線胴部(7a)、及後凸；緣部(18e)、及前凸緣部(8)。前凸緣部(8)，是具有：從捲線胴部(7a)的前端部朝徑方向外方突出的第1突出部(17a)、及從第1突出部(17a)的前端部朝向前端部側擴徑地朝前方突出的第1傾斜部(17b)。後凸緣部(18e)，是具有：從捲線胴部(7a)的後端部成為與第1突出部(17a)的徑方向長度(A)略相同長度地朝徑方向外方突出的第2突出部(18a)、及與第1傾斜部(17b)的徑方向長度(C)略相同長度地從第2突出部(18a)的前端部朝向後端部側擴徑的方式朝後方突出的第2傾斜部(18b)。
