PROBLEM TO BE SOLVED: To enable highly stable and effcient cutting.SOLUTION: This cutting instrument includes: an elongated member including a tubular part 1305 and a shaft-like part 1301 inserted in the tubular part 1305 a blade 1302 provided at one end of the elongated member, including a rotary shaft in the center, and including edges in two positions sandwiching the rotary shaft an operation part provided at the other end of the elongated member, and relatively linearly moving the tubular part 1305 and the shaft-like part 1301 and a movement mechanism for changing the relative linear movement of the tubular part 1305 and the shaft-like part 1301 generated by operation of the operation part into turning of the blade 1302, and turning the blade between a storage position where the blade is stored inside the elongated member and a projection position where the edges are projected in two directions outside the elongated member. The edges of the blade 1302 project from the elongated member, and the blade is moved toward the operation part while rotating the elongated member, so that the cutting instrument bores a hole having a diameter larger than the outer diameter of the tubular part 1305.COPYRIGHT: (C)2013,JPO&INPIT【課題】切削効率が高くかつ、安定性の高い切削を実現すること。【解決手段】 筒状部1305と、筒状部1305に挿入された軸状部1301とを含む長尺部材と、長尺部材の一端に設けられ、中央に回動軸を備え、回動軸を挟む2つの位置に刃を備えたブレード1302と、長尺部材の他端に設けられ、筒状部1305と軸状部1301とを相対的に直線移動させる操作部と、操作部の操作によって生じた筒状部1305と軸状部1301との相対的な直線移動を、ブレード1302の回動に変更し、長尺部材の内部に収容された収容位置と、長尺部材の外部2方向に刃を突出させた突出位置との間でブレードを回動させる運動機構と、を含み、ブレード1302の刃が長尺部材から突出した状態で、長尺部材を回転させつつ操作部側へ移動させることにより、筒状部1305の外径よりも大きな径の穴を穿孔する。【選択図】 図13
