An image forming apparatus includes: rasterization processors that rasterize input image data and generate raster image data; a predictor that predicts a rasterization processing time required for the rasterization processors to rasterize input image data of a unit to be subjected to an image formation process on each recording paper sheet; a hardware processor that determines an order in which the rasterization processors rasterize the input image data of the unit; an image former that performs the image formation process based on the raster image data; a sheet ejection processor that acquires, from the image former, each recording paper sheet subjected to the image formation process, and performs a sheet ejection process; and the hardware processor that determines an order of the recording paper sheets to be ejected by the sheet eject processor, to adjust the order of the recording paper sheets to an order of pages.