< Topic >The occasion where the stab it does, there are no times when collapsing and rising occur in the outside needle, they offer the stab tool whose stab resistance is small.SolutionsStab tool 1, outside is provided in outside needle 2 of air and that basic end needle hub inserting into 3 and outside needle 2, while being provided in the inside needle 4 of the air which is used and that basic end it possesses with needle hub 5. The inside needle 4, from advanced side, the tip 41 of the sharp needle and major diameter almost facing to fixed small diameter section, 42 and basic edge direction the intermediate section 43 which consists of the taper section which major diameter increases and small diameter section 42 compared to has with the large diameter section 44 whose inside diameter and major diameter are large respectively. In assembly state of stab tool 1, the tip 41 of the needle most has extended from advanced opening 24 of outside needle 2, the basic edge of small diameter section 42 and the point of large diameter section 4 have been located inside outside needle 2. In addition, outside in the region L1 which covers the small diameter section 42 of the inside needle 4 inside diameter of needle 2, is smaller than large diameter section 44 of the inside needle 4.< Selective figure >Figure 4【課題】穿刺した際、外針に潰れや盛り上がりが生ずることがなく、穿刺抵抗が小さい穿刺具を提供する。【解決手段】穿刺具1は、中空の外針2と、その基端部に設けられた外針ハブ3と、外針2内に挿入して使用される中空の内針4と、その基端部に設けられた内針ハブ5とを有する。内針4は、先端側から、鋭利な針先41と、外径がほぼ一定の小径部42と、基端方向へ向かって外径が漸増するテーパ部で構成される中間部43と、小径部42より内径および外径がそれぞれ大きい大径部44とを有する。穿刺具1の組み立て状態では、針先41が外針2の先端開口24から最も突出しており、小径部42の基端および大径部4の先端が外針2の内部に位置している。また、内針4の小径部42を覆う部位L1における外針2の内径が、内針4の大径部44より小さい。【選択図】図4
