In a case where another first region exists which faces the edge pixel across a second region on a line in a predetermined direction passing through the edge pixel of the first region, the correcting unit selects a correction amount for correcting the exposure amount applied by the exposing unit for the pixel to be corrected from information describing a plurality of correction amounts in accordance with a first number of pixels being a number of pixels on the line within the second region between the first region and the other first region and corrects the exposure amount for the pixel to be corrected in accordance with the selected correction amount.