Abstract: A high-frequency treatment tool comprising: a flexible sheath to be inserted into a treatment tool insertion channel of an endoscope; a treatment tool body provided inside the flexible sheath and comprising: a flexible cord; and a high-frequency knife to which a high-frequency current is applied, formed to the front end of the flexible cord; and a hard cylinder having an electrical insulating property, inserted and fixed inside the flexible sheath, wherein the high-frequency knife comprises blade portions radially provided in its axial direction, each of the blade portions including an engaging part, and wherein, when the high-frequency knife is made to stick out from the hard cylinder, engaging parts of the blade portions abut against a rear end portion of the hard cylinder so that: the high-frequency knife is engaged with the hard cylinder; and communicating channels that communicate an inside and an outside of the flexible sheath are formed between the blade portions adjacent to each other.

Abstract: A flexible tube is placed in large and small furnaces separated by a heat-shield panel, and two kinds of jacket resin of the flexible tube are heated separately at different temperatures for their own softening points. A connecting area of the jacket resin enters the small furnace to a predetermined distance. In this connecting area, the jacket resin fails to reach the softening point temperature, and is not firmly welded to a blade. A cylindrical attachment is used to surround the spot that has lower temperature than the softening point, and hot air of approximately 250° C. is supplied from a spot heater into the cylindrical attachment. The spot in the cylindrical attachment reaches the softening point in a short time, and the jacket resin is welded to the blade.

Abstract: A high-frequency treatment tool comprising: a flexible sheath to be inserted into a treatment tool insertion channel of an endoscope; a treatment tool body provided inside the flexible sheath and comprising: a flexible cord; and a high-frequency knife to which a high-frequency current is applied, formed to the front end of the flexible cord; and a hard cylinder having an electrical insulating property, inserted and fixed inside the flexible sheath, wherein the high-frequency knife comprises blade portions radially provided in its axial direction, each of the blade portions including an engaging part, and wherein, when the high-frequency knife is made to stick out from the hard cylinder, engaging parts of the blade portions abut against a rear end portion of the hard cylinder so that: the high-frequency knife is engaged with the hard cylinder; and communicating channels that communicate an inside and an outside of the flexible sheath are formed between the blade portions adjacent to each other.