PROBLEM TO BE SOLVED: To provide an endoscope apparatus capable of detecting a curved shape of an insertion tube with higher accuracy.SOLUTION: An endoscope apparatus comprises: an endoscope having a flexible insertion tube； an optical fiber for propagating detection light； a detected part provided to at least a portion of the optical fiber； and a curved shape detection sensor for detecting the curved shape of the insertion tube on the basis of the fact that a characteristic of the detection light transmitted through the detected part changes in response to a change of the curved shape of the optical fiber when the optical fiber is curved. A portion of the optical fiber or a portion of a guide member through which the optical fiber is inserted is retained by a constituent member having high torsional rigidity, which is a part of a guide member constituting the insertion tube.【課題】挿入管の湾曲形状をより精度良く検出可能な内視鏡装置を提供する。【解決手段】可撓性の挿入管を有する内視鏡と、検出光を伝搬する光ファイバと、光ファイバの少なくとも一部に設けられた被検出部とを有し、光ファイバの湾曲時に光ファイバの湾曲形状の変化に応じて被検出部を経た検出光の特性が変化することに基づいて挿入管の湾曲形状を検出する湾曲形状検出センサと、を具備する内視鏡装置である。光ファイバの一部、又は光ファイバが挿通されるガイド部材の一部が、挿入管を構成している構成部材の中でねじり剛性の大きい構成部材に保持されている。【選択図】図４
