STRUCTURE OF TREATMENT INSTRUMENT INSERTION PART OF ENDOSCOPE

PROBLEM TO BE SOLVED: To provide a structure of a treatment instrument insertion part of an endoscope, without looseness in a treatment instrument insertion cap pressed and fixed by a fixing nut, without requiring the treatment instrument insertion cap to be divided into a plurality of parts, excellent in the cost performance and the assembly workability, and without hygienic demerits. SOLUTION: A D-cut engagement part 15 where planes abut to each other is formed on the inner peripheral surface of a treatment instrument insertion cap attaching hole 2 and the opposite outer peripheral surface of the treatment instrument insertion cap 7. The minimum inner diameter of the treatment instrument insertion cap attaching hole 2 in the D-cut engagement part 15 is larger than the maximum outer diameter of the treatment instrument insertion cap 7 so that the treatment instrument insertion cap 7 is rotatable in the axial direction within the treatment instrument insertion cap attaching hole 2 while the treatment instrument insertion cap 7 is not pressed/fixed by the fixing nut 11. COPYRIGHT: (C)2010,JPO&INPIT