As for this invention, although being simple constitution, removing influence of reflection of measuring beam from the reflecting interface of light condensing optical system from the optical interference fault picture effectively, high picture quality the probe and the optical interference fault picture acquisition method of using for the optical interference fault picture acquisition device and the optical interference fault picture acquisition device which can form the optical interference fault picture are offered. From coupler BS reference optical path to reference mirror RM, is made longer than measurement optical path to light condensing position FP of suffering inspection body S from coupler BS. Because of this, assuming, that reflected light from the both sides of balance plate PP, ripple mark WS1 of pulse condition and WS2 occurred reference beam by interfering, be able to separate ripple mark WS3 and the signal which show the organization of suffering inspection body S, the ripple mark WS3 which is acquired at the position where at the same time it is close to starting point coherent characteristic being satisfactory, because signal-noise ratio of the signal becomes large, being based even in this, means with to be able to form the fault picture whose precision is good.本発明は、簡素な構成でありながら、集光光学系の反射面からの測定光の反射の影響を光干渉断層画像から有効に取り除いて、高画質な光干渉断層画像を形成することが出来る光干渉断層画像取得装置、光干渉断層画像取得装置に用いるプローブ及び光干渉断層画像取得方法を提供する。カプラBSから参照ミラーRMまでの参照光路長を、カプラBSから被検体Sの集光位置FPまでの測定光路長より長くしている。これにより、平行平板PPの両面からの反射光が、参照光と干渉することによって、パルス状の波形WS1,WS2が生じたとしても、被検体Sの組織を示す波形WS3と信号を分離でき、かつ原点に近い位置で取得される波形WS3は可干渉性が良好で信号のSN比が大きくなるため、これにも基づいて精度の良い断層画像を形成できることとなる。
