To efficiently receive interference light by a light-receiving element even when a temperature change occurs within the apparatus.SOLUTION: An optical interference tomographic apparatus includes: an optical fiber for guiding multiplexed light obtained by multiplexing return light from a subject projected with measurement light and reference light corresponding to the measurement light； a first lens for guiding light from the emission end of the optical fiber to a diffraction grating； a second lens for guiding light from the diffraction grating to a light-receiving element which includes a plurality of pixels； and at least one lens barrel which surrounds an optical path including the first lens and an optical path including the second lens, and in which are disposed the emission end of the optical fiber, the first lens, the diffraction grating, the second lens, and the light-receiving element.SELECTED DRAWING: Figure 6【課題】 装置内部において温度変化が生じた場合でも、干渉光を受光素子で効率的に受光する。【解決手段】 光干渉断層撮影装置は、測定光を照射した被検査物からの戻り光と測定光に対応する参照光とを合波して得た合波光を導光する光ファイバと、光ファイバの射出端からの光を、回折格子に導光する第１のレンズと、回折格子からの光を、複数の画素を含む受光素子に導光する第２のレンズと、第１のレンズを含む光路及び第２のレンズを含む光路を囲う少なくとも１つの鏡筒であって、光ファイバの射出端と第１のレンズと回折格子と第２のレンズと受光素子とが配置される鏡筒と、を有する。【選択図】 図６
