An apparatus has an optical system (200) detecting spectral information and having an optical scanner (23) and a driving unit (50) changing the optical path length by moving an optical member (31), a monitor (75), and a unit (70) controlling the driving unit, obtaining a tomographic image by performing Fourier analysis on the information and displaying the obtained image, in which a front surface of an examined object is positioned on the back side of a depth position where optical path lengths of measurement light and reference light become equal to obtain a normal image of the tomographic image, the front surface of the examined object is positioned on the front side of the depth position to obtain an inverted image of the tomographic image, and at least one of dispersion correction processing corresponding to the information and image combining processing is performed on both normal and inverted images, and the images are displayed.
