PROBLEM TO BE SOLVED: To provide a medical device capable of suppressing the occurrence of excessive bending and friction of another long device and improving the operability of the other device. A medical device (10) having a lumen (36) through which a long treatment device (90) can be inserted, a shaft (20) having a tip and a proximal end, a tip opening (33), a proximal opening (34), and a proximal end opening (34). The wall portion 35 includes a wall portion 35 extending between the tip end opening 33 and the proximal end opening 34 to form a lumen 36, and has a tubular body 30 fixed to the tip end portion of the shaft 20, and the wall portion 35 is a tubular body. A first groove 41, a second groove 42, a third groove 43, and a fourth groove 44 extending in the circumferential direction Y are formed on the outer peripheral surface of the 30. [Selection diagram] Fig. 3【課題】他の長尺なデバイスの過度な屈曲や摩擦の発生を抑制し、他のデバイスの操作性を向上可能である医療デバイスを提供する。【解決手段】長尺な治療デバイス９０を挿通可能な内腔３６が形成された医療デバイス１０であって、先端部と基端部を有するシャフト２０と、先端開口３３、基端開口３４、および先端開口３３と基端開口３４との間に延び内腔３６を形成する壁部３５を備え、シャフト２０の先端部に固定された管状体３０と、を有し、壁部３５は、管状体３０の外周面に周方向Ｙに延びる第１の溝４１、第２の溝４２、第３の溝４３および第４の溝４４が形成されている。【選択図】図３
