This treatment instrument (1) for an endoscope is provided with a treatment section (2) for treatment, an operation wire (2) connected with the treatment section (2), a coil sheath (9) into which the operation wire (3) is inserted, an insulating tube (10) into which the coil sheath (9) is inserted, and an operation section (4) for operating the treatment section (2). The operation section (4) comprises a slider (15) rotatably connected with the operation wire (3), a body (13) to which the slider (15) is mounted movably forward and backward, and a rotational operation section (14) which is so mounted as to be rotatable with respect to the body (13) and has the coil sheath (9) so mounted thereto as to be not rotatable. The distal end of the insulating tube (10) is mounted rotatably and movably forward and backward to the distal end of the coil sheath (9). The proximal end side of the insulating tube (10) is separated in a manner so that the proximal end side is relatively movable in an axial direction with respect to the coil sheath (9) and covered with the operation section (4) so as not to be exposed even when the coil sheath (9) curves.
