PROBLEM TO BE SOLVED: To provide an inversion prevention mechanism for a fishing reel in which assembly property of a cam to a rotor is improved.SOLUTION: An inversion prevention mechanism for a fishing reel comprises: an inversion prevention gear 12； an inversion prevention claw 20 which is engaged to the inversion prevention gear 12； and a cam 30 which controls the inversion prevention claw 20 so as to engage and disengage to/from the inversion prevention gear 12. The cam 30 comprises: a friction holding body 31 which holds a rotor 10 and rotates with the rotor 10 by friction force with the rotor 10； and an energization member 32 which energizes the friction holding body 31 in a closing direction at all times. The friction holding body 31 comprises two holding parts 33, 34 for holding the rotor 10, a connection part 35 for connecting the two holding parts 33, 34 so as to be opened and closed freely, and an engagement part 36 which is engaged to the inversion prevention claw 20. The two holding parts 33, 34 are integrated so that they cannot be separated.SELECTED DRAWING: Figure 6【課題】カムの回転体への組み付け性が向上した魚釣用リールの逆転防止機構を提供する。【解決手段】魚釣用リールの逆転防止機構は、逆転防止歯車１２と、逆転防止歯車１２に係合する逆転防止爪２０と、逆転防止歯車１２に逆転防止爪２０を係脱制御するカム３０とを備え、カム３０は、回転体１０に挟着し、回転体１０との摩擦力により回転体１０とともに回転する摩擦挟着体３１と、摩擦挟着体３１を常時閉じる方向に付勢する付勢部材３２とを備え、摩擦挟着体３１は、回転体１０を挟む２つの挟着部３３，３４と、２つの挟着部３３，３４を開閉自在に連結する連結部３５と、逆転防止爪２０と係合する係合部３６とを備え、前記２つの挟着部３３，３４が分離不可能に一体に形成されている。【選択図】図６
