PROBLEM TO BE SOLVED: To provide an indwelling needle with excellent operability, capable of protecting a sharp terminal of an inner needle by a protector simultaneously with an extracting operation of the inner needle.SOLUTION: An erroneous puncture prevention member includes a protector 7P, a gate 7G and a gate holding part 7F. When an inner needle 2N is moved in a direction of a proximal end DE, a hooking part 2NDS of the inner needle 2N is hooked to a hooking part FDS of the gate holding part 7F. When the inner needle 2N is pulled and moved in the direction of a proximal end PE further, the gate holding part 7F is pulled further in the direction of the proximal end PE of the protector 7P, and the side of the proximal end PE of the gate holding part 7F is abutted to the side of the proximal end PE of the protector 7P. The gate 7G is pulled into the side of a terminal DE of the protector 7P, and the gate 7G closes an opening 7PODE on the side of the terminal DE of the protector 7P. The protector 7P can be detached from a hemostatic valve member 5 in the state of protecting the sharp terminal of the inner needle.COPYRIGHT: (C)2014,JPO&INPIT【課題】内針の抜去操作と同時に、プロテクターで内針の鋭利な末端を保護することのできる操作性に優れた留置針を提供すること。【解決手段】誤刺防止部材は、プロテクター7Pと、ゲート7G及びゲート保持部7Fを有する。内針2Nは、基端DE方向に移動させると、内針2Nの掛止部2NDSが、ゲート保持部7Fの掛止部FDSに掛止される。さらに内針2Nを基端PE方向に引いて移動させると、ゲート保持部7Fは、プロテクター7Pのさらに基端PE方向に引き込まれ、ゲート保持部7Fの基端PE側が、当該プロテクター7Pの基端PE側に突き当たる。ゲート7Gは、プロテクター7Pの末端DE側に引き込まれ、ゲート7Gはプロテクター7Pの末端DE側の開口部7PODEを閉鎖する。プロテクター7Pは、内針の鋭利な末端を保護した状態で、止血弁部材5から離脱することができる。【選択図】図5