Patent ID: 7645278

Claim:
A coagulating cutter comprising: a transmitting member for transmitting energy, for treating living body tissue, to the living body tissue; an outer sheath through which the transmitting member is passed; a grasping section supported at the tip end portion of the outer sheath so as to be capable of turning with respect to the transmitting member, which allows the living body tissue to be grasped against the transmitting member, a surface of the grasping section facing a surface of the transmitting member; a recess located at a center position along a longitudinal direction of one of the facing surfaces of the transmitting member and the grasping section; and a protrusion extending over a predetermined length in a longitudinal direction of the other of the facing surfaces of the transmitting member and the grasping section, the protrusion being configured to fit into the recess such that a gap of a predetermined dimension is formed between the facing surfaces of the transmitting member and the grasping section, wherein, when the grasping section is turned toward the transmitting member into a closed state, the protrusion fits into the recess and is in a surface contact with the recess to form a contact portion for incising the living body tissue, the facing surfaces of the transmitting member and the grasping section, which are positioned on both sides of the contact portion and which have the gap of the predetermined dimension, form a non-contact portion operable for coagulating the grasped living body tissue, and the gap of the predetermined dimension of the non-contact portion is formed so as to be enlarged in a stepped manner with an increase in a distance from each side of the recess and the protrusion.