A medical treatment endoscope (1300) according to the present invention is provided with: a flexible sheath capable of a bending operation an arm section (302A, 302B) protruding from the tip of the sheath and capable of a bending operation an operation stick (1354A, 1354b) 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 (302A, 302B) 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 (1354A, 1354b) detachably. This configuration provides a medical treatment endoscope capable of conducting maneuvering while facilitating sterilization for obtaining a high degree of cleanliness.