The present invention when it is fishing, move or fishing location, put the needle and gimmicks such as fishing line The space to stop the fishing line to a simple and instant when it is provided, and to provide a reel for fishing line stop assisting device to help improve the safety and working convenience. A to the precursor of the fishing line stop auxiliary vessel was fitted with a rubber O-type ring 3 for the fishing line stop, and interleaving between the rubber O-shaped ring 3 while straight to pull the fishing line 2, fishing line stop function is I realize. And, the upper lid is capable to open and close, replace the rubber O-shaped ring 3 are also possible. It helps to the improvement of the repeated use and working convenience function.BACKGROUND 1【課題】釣りをした際、釣り場所の移動あるいは、釣糸に針や仕掛け等を付ける際に簡単で瞬時に釣糸を止める空間を設け、安全性や作業利便性の向上に役立つリール用釣糸止め補助器を提供する。【解決手段】釣糸止め補助器の躯体部に釣糸止め用のゴム製O型リング3を装着し、釣糸2をまっすぐに引っ張りながらゴム製O型リング3の間に入れ込むと、釣糸止め機能が実現する。且つ、上部蓋は開閉することが可能であり、ゴム製O型リング3の交換も可能である。繰返し使用や作業利便性機能の向上に役立つ。【選択図】図1