PROBLEM TO BE SOLVED: To provide an OCT apparatus for making it easy to construct at least a reference optical system to be compact.SOLUTION: An OCT apparatus including an optical splitter 130, comprising an OCT optical system 100 for detecting a spectral interference signal between measurement light and reference light, and capable of acquiring OCT data on a subjects eye by processing the spectral interference signal output from the OCT optical system 100 comprises: an optical scanner 156 for deflecting the measurement light from the optical splitter 130 to perform a scan on the subjects eye Es tissue an objective optical system 158 for guiding measurement light from the optical scanner 156 to the subjects eye E a first switching unit that with respect to an optical axis direction, switches a relative position between a focus of the objective optical system 158 and the optical scanner 156 and a second switching unit that switches an optical path length between the optical splitter 130 and the optical scanner 156 in a measurement optical path to cancel at least part of a variation in an optical path length difference between the measurement optical path and a reference optical path caused by the relative position being switched by the first switching unit.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2019,JPO&INPIT【課題】少なくとも参照光学系をコンパクトに構成しやすいOCT装置を提供する。【解決手段】光分割器130を有し、測定光と参照光とのスペクトル干渉信号を検出するOCT光学系100を備え、OCT光学系100から出力されるスペクトル干渉信号を処理して被検眼のOCTデータを取得可能なOCT装置であって、光分割器130からの測定光を偏向し、被検眼Eの組織上で走査する光スキャナ156と、光スキャナ156からの測定光を被検眼Eへ導く対物光学系158と、対物光学系158の焦点と光スキャナ156との相対位置を光軸方向に関して切替える第1切替部と、測定光路における光分割部130と光スキャナ156との間の光路長を切替えることで、第1切替部によって相対位置が切替えられることによる測定光路と参照光路との光路長差の変化の少なくとも一部を相殺する、第2切替部と、を備える。【選択図】図1
