Endoscope including bending operation mechanism

An endoscope comprising:

• an operating section housing a bending operation mechanism to give an instruction to bend a bending section provided on a distal end side of an elongated insertion section, the bending operation mechanism comprising:
• an operating lever for providing the instruction to the bending section, the lever being tiltable with respect to a fulcrum;
• a frame including the fulcrum, the frame having an opening through which the operating lever is placed, the frame having a frame wall formed at the opening, the frame including one of a positioning projection or hole on an outer peripheral side of the frame;
• a boot disposed to cover the opening in the frame, the boot including a watertight fixing portion that contacts with an outer peripheral surface of the frame wall, the watertight fixing portion being provided in a peripheral portion of the boot and having a circular cross section;
• a first fixing ring having an other of the positioning projection or hole engaged with the one of the positioning projection or hole of the frame, the first fixing ring having an interior surface pressing the watertight fixing portion in a radial direction of the opening, from an outer peripheral side of the watertight fixing portion of the boot toward the outer peripheral surface of the frame wall so as to maintain an inside of the frame watertight;
• and
• a second fixing ring having a first threaded surface engaging a second threaded surface disposed on the outer peripheral surface of the frame, the second fixing ring sliding over an outer peripheral surface of the first fixing ring to engage the first threaded surface with the second threaded surface and to fix the first fixing ring by pressing the interior surface of the first fixing ring against the watertight fixing portion.