An OCT apparatus (1) includes an OCT optical system (100) that has a light splitter (104) splitting light from an OCT light source (102) to light travelling to a measurement light path (152) and light travelling to a reference light path (106) and a detector (120) detecting a spectrum interference signal of measurement light guided to a subject eye (E) through the measurement light path (152) and reference light from the reference light path (106), and a processing unit (70) that processes the spectrum interference signal to generate OCT data. The processing unit (70) performs at least complementary processing on an overlapping region of a real image (R) and a virtual image (M) in OCT data based on a plurality of OCT data obtained with different optical path lengths when detecting the spectrum interference signal, and generates OCT data subjected to the complementary processing.
