It is possible to change the direction of the loop forming member, and provide a hand-operated hook and medical snare.The hook 10 comprises a cylindrical member 11 having an inner hole 11a penetrating therethrough and a loop forming member 12 inserted into the inner hole 11a of the cylindrical member 11. The loop forming member 12 has first and second pieces 13 and 14 which are connected to each other, and the base ends 13b and 14b of the first and second pieces 13 and 14 are movable in the longitudinal direction Z of the tubular member 11, respectively.ループ形成部材の向きを変化させることができ、操作性の良い引っ掛け具及び医療用スネアを提供する。 引っ掛け具１０は、貫通する内孔１１ａを有する筒部材１１と、筒部材１１の内孔１１ａに挿通されるループ形成部材１２とを備える。ループ形成部材１２は、先端同士が繋がった第１、第２の片１３、１４を有しており、第１、第２の各片１３、１４の基端１３ｂ、１４ｂは、それぞれ筒部材１１の長さ方向Ｚに移動可能とされる。
