A treatment apparatus comprising: a flexible tube section which has a longitudinal axis and is extended in longitudinal directions; a distal-end treatment section which is provided to a distal-end direction side of the flexible tube section and which is rotatable in periaxial directions with respect to the flexible tube section; a rotor which is provided between the distal-end treatment section and the flexible tube section and which is rotatable together with the distal-end treatment section in the periaxial directions with respect to the flexible tube section; a rotational operation section which is provided to a proximal-end direction side of the flexible tube section and which is configured to perform a rotational operation of the distal-end treatment section; a rotational operation wire (21A,21B) which is configured to be pulled or loosened by the rotational operation section to rotate the distal-end treatment section; a wire fixing portion which is provided to the rotor or to a part to the distal-end direction side of the rotor and to which a distal end of the rotational operation wire (21A,21B) is fixed; and a direction change portion (47A,47B) which is configured to change an extending direction of the rotational operation wire (21A,21B) extended on an outer peripheral surface of the rotor from the wire fixing portion, and configured to lead out the rotational operation wire (21A,21B) to the rotational operation section, wherein the direction change portion (47A, 47B) includes a convex portion (47A, 47B) which is provided on an outer peripheral surface of a distal-end direction side part of the flexible tube section or an outer peripheral surface of a different member fixed the flexible tube section and provided between the flexible tube section and the rotor and which protrudes toward an outer peripheral direction, the convex portion (47A, 47B) being configured to abut on the rotational operation wire (21A, 21B) extended on the outer peripheral surface of the rotor to change the extending direction of the rotational operation wire (21A, 21B), the rotational operation wire (21A, 21B) includes a first rotational operation wire which is extended from the wire fixing portion on the outer peripheral surface of the rotor along a first oblique direction inclined from the longitudinal directions toward the circumferential directions, and a second rotational operation wire which is extended on the outer peripheral surface of the rotor from the wire fixing portion along a second oblique direction inclined from the longitudinal directions toward the circumferential directions to a direction opposite to the first oblique direction, the convex portion (47A, 47B) includes a first convex portion on which the first rotational operation wire abuts, and a second convex portion on which the second rotational operation wire abuts, and the rotor includes a wire crossing portion at which the first rotational operation wire is configured to cross the second rotational operation wire on the outer peripheral surface, characterized in that the first convex portion includes a first root which is placed to be radially apart from the longitudinal axis of the flexible tube section by a first distance (a), and the second convex portion includes a second root which is placed to be radially apart from the longitudinal axis of the flexible tube section by a second distance (b) smaller than the first distance (a), a difference of the second distance (b) from the first distance (a) being not smaller than a diameter of each of the first rotational operation wire and the second rotational operation wire. a flexible tube section which has a longitudinal axis and is extended in longitudinal directions; a distal-end treatment section which is provided to a distal-end direction side of the flexible tube section and which is rotatable in periaxial directions with respect to the flexible tube section; a rotor which is provided between the distal-end treatment section and the flexible tube section and which is rotatable together with the distal-end treatment section in the periaxial directions with respect to the flexible tube section; a rotational operation section which is provided to a proximal-end direction side of the flexible tube section and which is configured to perform a rotational operation of the distal-end treatment section; a rotational operation wire (21A,21B) which is configured to be pulled or loosened by the rotational operation section to rotate the distal-end treatment section; a wire fixing portion which is provided to the rotor or to a part to the distal-end direction side of the rotor and to which a distal end of the rotational operation wire (21A,21B) is fixed; and a direction change portion (47A,47B) which is configured to change an extending direction of the rotational operation wire (21A,21B) extended on an outer peripheral surface of the rotor from the wire fixing portion, and configured to lead out the rotational operation wire (21A,21B) to the rotational operation section,