The tissue sampling device includes a flexible sheath 34, a needle tube 35 which is inserted into the sheath 34 so as to freely advance and retreat, a needle tube 35 which is punctured into the living tissue, and a needle tube 35 which is provided on the proximal end side of the sheath 34 and operates the forward and backward movement of the needle tube 35 And an operation unit. The needle tube 35 has a distal end portion having a slit 50 extending from the distal end opening 35 c toward the proximal end side. When the distal end portion of the needle tube 35 protrudes from the distal end of the sheath 34, when viewed from the axial direction of the needle tube 35 , And at least a portion of the distal end portion is located radially outward of the inner surface of the sheath.組織採取装置は、可撓性を有するシース34と、シース34に進退自在に挿通され、生体組織に穿刺される針管35と、シース34の基端側に設けられ、針管35の進退を操作する操作部と、を備える。この針管35は、先端開口35cから基端側に向けて延びるスリット50を備えた先端部を有し、その先端部がシース34の先端から突出した状態のとき、針管35の軸方向から見て、先端部の少なくとも一部分がシースの内面よりも径方向外側に位置する。
