Disclosed is a device for resecting an organ in a cavity of a living body. The device includes a guide with a tube and a tube, both cylindrical, the tube being mounted in the first tube； an electrical conductor surrounded by an electrically insulating sheath, the tube being a cylinder of revolution with an inner radius of value R1, the tube including a part which is a cylinder of revolution with an outer radius of value R2<；R1 and with an angle at the center of a value Ac, and a part which is not a cylinder of revolution and has an angle at the center of value “360°−Ac”； the insulated conductor contacts the part of the tube, between the outer and inner walls of this tube； and a unit for keeping this insulated conductor in contact with the part of the tube.
