According to one aspect of the present invention, there is disclosed a treatment sheath for endoscopic blood vessel harvesting, comprising a sheath main unit which can be inserted into a body through a cut skin portion in order to harvest a blood vessel in the body, a channel which is formed along a longitudinal direction in the sheath main unit and through which an endoscope is inserted so as to be insertable/detachable, a blood vessel holding member which is disposed at the sheath main unit and which holds the blood vessel to be harvested; and a blood vessel cutting device which is disposed at the sheath main unit and is positioned substantially symmetrically with the blood vessel holding member with respect to the channel and which cuts the blood vessel to be harvested.