PROBLEM TO BE SOLVED: To facilitate acquisition of a fundus tomographic image of an eye with a short axial length.SOLUTION: A fundus photographing apparatus includes: an interference optical system allowing a light detector to receive interference signal light that is generated by interference between measurement light from a measurement optical system and reflected against a fundus of a subject and reference light from a reference optical system and an optical path length varying optical member which is arranged in an optical path of the measurement optical system or the reference optical system and is moved in an optical axis direction by a drive section in order to adjust an optical path length difference between the measurement light and the reference light. The fundus photographing apparatus acquires a fundus tomographic image, based on a signal to be output from a light receiving element. The apparatus further includes an optical path length extension unit which is arranged in the optical path of the measurement optical system and extends the optical path length of the measurement optical path with respect to an optical path length variable range by the drive of the optical path length varying optical member.COPYRIGHT: (C)2014,JPO&INPIT【課題】 眼軸長が短い眼の眼底断層像を容易に取得する。【解決手段】 被検物眼底で反射された測定光学系からの測定光と参照光学系からの参照光との干渉により生じた干渉信号光を光検出器により受光する干渉光学系と、測定光学系又は参照光学系光路中に配置され、測定光と参照光との光路長差を調整するために駆動部により光軸方向に移動される光路長可変用光学部材と、を備え、受光素子から出力される信号に基づいて眼底断層像を得る眼底撮影装置において、測定光学系の光路中に配置され、光路長可変用光学部材の駆動による光路長可変範囲に対して測定光路の光路長を延長させる光路長延長ユニットを備える。【選択図】 図1
