An image processing apparatus of the present invention performs halftone processing with respect to first image data to generate second image data. In such a case, based on a threshold and values of a plurality of pixels in a reference area that includes a target pixel of first image data, whether or not the target pixel is included in an edge portion is determined, and a pixel value of second image data corresponding to the target pixel determined to be included in the edge portion is corrected by using correction data generated from the value of the target pixel.