To provide an image forming apparatus capable of obtaining an accurately corrected printed matter without being affected by the longitudinal and lateral printing/layout printing of a paper sheet even when the corrected image and the uncorrected image of image data coexist in a storage device in the image forming apparatus.

In the image forming apparatus, a registration correction means 408 performs misregistration correction for the image data in pixel units based on misregistration correction amount. A correction flag processing part 114 adds a correction flag to the image data so as to discriminate whether or not the image data shows the image whose misregistration is corrected. When the image data is printed and output, whether or not reverse correcting processing is performed to the image data is decided based on at least either the existence of the correction flag of the image data or a paper scanning direction in the color image forming apparatus.