The present invention can easily sample a sufficient amount of body tissue enough to make a pathological definitive diagnosis. A tissue sampling device according to an embodiment of the present invention includes: a flexible sheath 34； a cannula 35 inserted into the sheath 34 so as to be movable back and forth and punctured into body tissue； and an operation unit provided on a proximal end side of the sheath 34 to move the cannula 35 back and forth. The cannula 35 has a distal end part including a slit 50 extending from a distal end opening 35c toward a proximal end side.
