An inspection method according to the embodiments includes applying light of a light source to an inspection target; receiving light from the inspection target to obtain a first image of the inspection target by a sensor; based on an image of a first pattern comprising repetitive patterns unresolvable with a wavelength of the light source in the first image, calculating a deviation of luminance values with respect to each of first regions in the first pattern by a processor; obtaining a second image of the inspection target by the sensor; correcting luminance values of the second image by the processor based on the deviations of the luminance values; and comparing the repetitive patterns of the corrected second image with each other by a comparer.