An image processing apparatus processes data for printing an image by relatively moving a printing unit and a printing medium. The printing unit includes a plurality of printing elements arranged in a first direction, and the relative movement is in a second direction that intersects with the first. The apparatus includes an acquisition unit to acquire image data corresponding to an image of one page, a first processing unit to process first image data corresponding to a first processing area of the image by using a common parameter for each pixel arranged in the second direction, for generating first print data that is used for the printing unit, a second processing unit to process second image data corresponding to a second processing area of the image by using a common parameter for each pixel arranged in the second direction, for generating second print data used for the printing unit.