Surgical apparatus for endoscope and exterior tube

A surgical apparatus for an endoscope comprising:

• an outer tube that guides an insertion part of a medical instrument into a body cavity, wherein the outer tube includes
• an outer tube body having a distal end, a base end, and a longitudinal axis,
• a first distal end opening and a second distal end opening provided at the distal end of the outer tube body,
• a first base end opening and a second base end opening provided at the base end of the outer tube body,
• a first insertion passage that is provided along the longitudinal axis of the outer tube body, and allows the first distal end opening and the first base end opening to communicate with each other and a first medical instrument to be inserted therethrough so as to be movable forward and backward,
• a second insertion passage that is provided along the longitudinal axis of the outer tube body, allows the second distal end opening and the second base end opening to communicate with each other, and has a second medical instrument inserted therethrough to be movable forward and backward, and
• an interlocking member that has a first coupling part to be coupled to the first medical instrument inserted through the first insertion passage and a second coupling part to be coupled to the second medical instrument inserted through the second insertion passage, and is movable forward and backward inside the outer tube body;
• and
• an exterior tube, wherein the outer tube is sheathed within the exterior tube,
• wherein the exterior tube includes
• an exterior tube main body having a base end, a distal end, and a longitudinal axis,
• a distal end opening provided at the distal end of the exterior tube main body,
• a base end opening provided at the base end of the exterior tube main body,
• an insertion passage that is provided along the longitudinal axis of the exterior tube main body, and allows the distal end opening and the base end opening to communicate with each other and the outer tube to be inserted therethrough,
• a locking part that has a longitudinal recess or protrusion having a shape elongated along the longitudinal axis and formed along the longitudinal axis in an outer peripheral surface of the exterior tube main body and prevents a rotation of the exterior tube main body about the longitudinal axis, and
• a supply port opening to a base end side of the exterior tube main body.