An image forming apparatus according to the present invention is capable of executing printing processes for color images and monochromatic images and comprises a printer section capable of executing processes for color printing and monochromatic printing and a printing task management section for receiving a plurality of printing jobs including color printing jobs and monochromatic printing jobs as input, computationally determining the processing time required for each of the printing processes on the basis of the information indicating color printing or monochromatic printing and the information indicating the number of copies to be printed and outputting the data of the printing jobs of short processing time separately for monochromatic printing and color printing with priority to the printer section.