An image processing apparatus can correct band-like unevenness due to flickering with a simple arrangement. For this purpose, the image processing apparatus includes a detecting unit which detects, in the image to be processed, a band-like unevenness occurring along a direction substantially perpendicular to the scanning direction of the imaging sensor included in the image-capturing apparatus used when performing image-capturing of the image, a calculating unit which calculates a correction amount to correct the band-like unevenness, and a correcting unit which corrects the band-like unevenness in the image based on the correction amount.