Provided is a medical device capable of determining a puncture state of a puncture member into a biological tissue and capable of holding the state where the puncture member is punctured into the biological tissue. A medical instrument includes a long puncture member that has a blade surface inclined with respect to an axial direction at a tip portion and can puncture a living tissue, and the puncture member is formed on the blade surface. Partitioning a dosing lumen that communicates with the outside through the dosing hole and one or more suction lumens that respectively communicate with the outside through one or more suction holes formed on the side surface, Among the suction holes, the suction hole located on the most distal end side communicates with the outside at a position opposite to the region where the blade surface is located in the circumferential direction. [Selection] Figure 2【課題】穿刺部材の生体組織への穿刺状態を判定可能であると共に、穿刺部材が生体組織に穿刺された状態を保持可能な医療器具を提供する。【解決手段】医療器具は、軸方向に対して傾斜した刃面を先端部に備えた、生体組織に穿刺可能な長尺状の穿刺部材を備え、前記穿刺部材は、前記刃面に形成された投与孔を通じて外部と連通している投与ルーメンと、側面に形成された１つ以上の吸引孔を通じてそれぞれ外部と連通している１つ以上の吸引ルーメンと、を区画し、前記１つ以上の吸引孔のうち最も先端側に位置する吸引孔は、周方向において、前記刃面が位置する領域と反対側の位置で外部に連通している。【選択図】図２
