A medical treatment system (1, 20, 40) including an endoscope (100), a treatment tool (50, 70, 71,72) that is inserted in a channel (29, 30, 81A, 81B, 81C,102, 103) of the endoscope, and a holder (2, 21, 41, 45) that holds the treatment tool in a manner that enables a user who operates the endoscope to move the treatment tool forward and backward and rotate the treatment tool, with the treatment tool having a treatment portion (51) that performs treatment on a living body a wire (52) for operating the treatment portion whose distal end is connected to the treatment portion a sheath portion (53) that has a first sheath (57) that is formed with a coil and in which the wire is inserted in a manner capable of moving forward and backward in the axial direction, and a second sheath (58) that is formed with a coil of a plurality of layers and provided on the outside of the first sheath and an operating portion (55) to which the base end of the wire is connected and enables forward/backward and rotation operation of the wire and with the holder holding the operating portion so as to be in a predetermined positional relation with respect to the endoscope.
