Treatment instrument for endoscope and endoscope system

A treatment instrument for an endoscope used in combination with an endoscope, the treatment instrument comprising:

• a sheath having flexibility;
• a treatment section disposed at a distal end of the sheath;
• and
• a manipulation unit disposed at a proximal end of the sheath and configured to manipulate the treatment section,
• wherein the sheath comprises:
• a sheath main body having a lumen extending along a longitudinal axis of the sheath;
• a transition section comprising an opening in communication with the lumen, the opening located at an intermediate section of the sheath main body;
• a metal member fitted onto a distal portion of the sheath main body and the metal member covering a circumference of the sheath main body;
• and
• a wire, wherein the wire extends through the lumen of the sheath main body, wherein a distal end of the wire is protruded from the opening of the transition section and the distal end of the wire is fixed to a proximal end portion of the metal member, and the wire configured to transmit rotational movement of a proximal end of the wire to the metal member;
• and
• wherein the sheath main body comprises a first tube and a second tube, the second tube connected to a distal end of the first tube,
• the first tube comprises the lumen and the opening,
• the second tube is covered by the metal member,
• the first tube has a first center,
• the metal member has a second center, and
• the first center is offset from the second center,
• wherein the manipulation unit comprises:
• a manipulation main body fixed to a proximal end of the sheath main body;
• and
• a handle attached to a proximal end of the wire protruded from the manipulation main body and the handle being configured to input rotational torque to the wire,
• wherein the wire comprises a plurality of individual wires, and
• wherein the plurality of individual wires are only fixed to each other at each of a proximal end of the plurality of wires and a distal end of the plurality of wires.