The bending operation wire fixing structure is disposed in the bending portion 7 of the insertion portion 2 and is disposed at the foremost end of the bending tube 30 having a plurality of bending pieces 31 and the flat portions 32 and 32a are formed. The distal end bending piece 31a, the bending operation wire 33 fixed to the distal end bending piece 31a to bend the bending portion 7, and the flat portion 32a. A fixed portion 40 that includes two communicating portions and that folds and fixes the bending operation wire 33 on the flat surface portion 32a. 湾曲操作ワイヤ固定構造は、挿入部２の湾曲部７内に配設され、複数の湾曲駒３１を備えた湾曲管３０と、湾曲管の最先端に配設され、平面部３２、３２ａが形成された先端湾曲駒３１ａと、先端湾曲駒３１ａに固定され、湾曲部７を湾曲操作する湾曲操作ワイヤ３３と、平面部３２ａに設けられ、先端湾曲駒の内側から外側に湾曲操作ワイヤ３３を通す２つの連通部を備え、湾曲操作ワイヤ３３を折り返して平面部３２ａ上で固定する固定部４０と、を具備する。
