PROBLEM TO BE SOLVED: To provide a hollow fiber for reinforcing a leader, which does not make a fish have wariness, not only prevents a leader from being cut by rubbing with fish teeth when a fishhook is swallowed by a fish but also easily carries out a fine adjustment such as change of a position and length of a part to be reinforced according to the kind of fish to be fished.SOLUTION: When the hollow fiber 1 for reinforcing a leader, which reinforces a fixed section in the vicinity of an end part at a side to be bound to a hook 3 in the leader 2 is used, the leader 2 is inserted into the inside of the hollow fiber and the hollow fiber is extended in the length direction so that the hollow fiber is stuck fast to the fixed section in the leader 2.COPYRIGHT: (C)2009,JPO&INPIT【課題】魚に警戒心を抱かせることなく、魚に釣針を飲み込まれた際に魚の歯が擦れてハリスが切れるのを防止するだけでなく、釣ろうとする魚の種類に応じて、補強する部分の場所や長さを変化させるなど、細かい調整も容易に行うことのできるハリス補強用中空糸を提供する。【解決手段】ハリス2における釣針3に結束される側の端部近傍の所定区間を補強するためのハリス補強用中空糸1を、使用時に、その内部にハリス2を挿入して長手方向に延伸させることにより、ハリス2における前記所定区間に密着させることができるようにした。【選択図】図5