There is disclosed a treatment device for an endoscope, comprising a treatment portion in which an operation wire is forward/backward moveably inserted into a main tube of an elongated flexible tube to be inserted into a body, a tip end of the operation wire forms a loop for treatment by itself in a projection state from the main tube, and the loop is adapted to be retractable and storable in the main tube, wherein the treatment portion is formed with a wire rope obtained by integrally intertwining a plurality of side strand wires with a core strand wire, and spiral convex or concave portions continuously disposed along the outer periphery of the wire rope are formed with the side strand wires. Therefore, there is provided a superior capability of accurately and remarkably easily capturing/fastening a living tissue with respect to an affected area such as a polyp, the containment capacity of the loop for treatment into the main tube is satisfactory, further the device is easily formed/processed and can be provided at a low cost, and further enhancement of the medical treatment property and enhancement of convenience are effectively achieved.
