An apparatus for generating a two-dimensional image of an object using an optical coherence tomography (OCT) optical system, includes: the OCT optical system including: a light source; a splitter for splitting light emitted from the light source into a measurement optical path and a reference optical path; a scanner arranged in the measurement optical path for scanning the object in at least one of XY directions with the split light; and a detector for detecting a spectrum of combined light of the split light from the measurement optical path reflected on the object and the split light from the reference optical path each XY position of the light on the object, and a processor for generating the two-dimensional image of the object in the XY directions by converting the number of zero cross points of an interference signal contained in the spectrum at each XY position into a luminance value.