A medical treatment endoscope according to the present invention is provided with: a flexible sheath capable of a bending operation an arm section protruding from the tip of the sheath and capable of a bending operation an operation stick formed to allow a procedure instrument to pass therethrough so that the operation stick is operated by an operator in an attempt to bend the arm section and a channel unit having a first channel which allows the procedure instrument to pass therethrough so that the channel unit is inserted through the operation stick detachably.
