An instrument for cutting a living tissue is provided to increase heat resistance to heat generated in an operation of cutting the living tissue and to ensure by stanch the blood of the tissue to be cut. The instrument for cutting a living tissue 41 includes a body part 422 having a distal end and a proximal end and on which a groove is formed through, a tissue holding part 423 made of an electrically insulating material, a slit groove 427 formed in the part where at least a part of the tissue holding part is arranged, a first electrode 425 arranged at the proximal end side of the slit groove, and a second electrode 424 arranged at the other side opposite to the side where the first electrode of the tissue holding part is arranged.
