Insertion instrument

An insertion instrument, comprising:

• an insertion portion including a bending portion provided at a distal end side of the insertion portion;
• a first wire provided in the insertion portion;
• and
• an operation portion provided at a proximal end side of the insertion portion,
• wherein the operation portion includes a bending operation unit,
• wherein the bending operation unit includes:
• a lever having a central shaft defining a central axis,
• a rotor coupled to the lever,
• a wire attachment surface to which the first wire is attached,
• wherein an inner surface of the operation portion includes a receiver body and a restriction body,
• wherein the receiver body supports the rotor for a rotation operation and for an inclination operation, wherein the rotation operation is rotation about the central axis and the inclination operation is movement of the lever from a neutral position to an inclined position, where, in the inclined position, the central shaft is inclined relative to the central shaft in the neutral position,
• wherein movement of the lever from the neutral position to the inclined position pulls the first wire to bend the bending portion,
• wherein the restriction body restricts the rotation operation centered at the central axis and allows the inclination operation in all directions,
• wherein the operation portion includes:
• a first outer shell forming a first portion of an outer surface of the operation portion, and
• a second outer shell bonded to the first outer shell and forming a second portion of the outer surface of the operation portion, and
• wherein at least one of the first outer shell and the second outer shell includes the restriction body.