An image processing apparatus that processes a plurality of tomographic signals corresponding to light of mutually different polarization, acquired from an object using light interference, extracts candidate regions for depolarization regions of the object in a retardation image of the object, based on retardation values of the object obtained using the plurality of tomographic signals, and extracts depolarization regions of the object in an image indicating uniformity of polarized light in candidate regions, based on a value indicating uniformity of polarized light of the candidate regions, obtained using the plurality of tomographic signals of the candidate regions.