Patent ID: 8764641

Claim:
A plug device provided at an outer surface of an endoscope and having a tubular opening portion that leads to a channel within the endoscope and a plug body unit detachably attached to the opening portion, the plug device comprising: a tubular plug body provided at the plug body unit and having a fitting hole to which the opening portion fits; an arm formed by cutting out a portion of the plug body and extending along an outer peripheral surface of the opening portion fitting into the fitting hole; a boss provided at a tip portion of the arm and protruding toward an outer peripheral surface of the opening portion; a locking groove formed at the outer peripheral surface of the opening portion and locking the boss when the opening portion fits to the fitting hole; and a cam groove formed at the outer peripheral surface of the opening portion continuously with the locking groove and guiding the boss in a direction in which the deflection of the arm increases from the locking groove with the displacement of the plug body unit by removal manipulation of the plug body unit, wherein an elastic limit of the arm is greater than a force which is applied by the deflection of the arm until the boss is locked by the locking groove and less than a force which is applied by the deflection of the arm until the boss reaches an end point of the cam groove wherein the boss is guided until the boss reaches an end point of the cam groove, and when the deflection of the arm exceeds an elastic limit, the arm breaks.