An image forming apparatus includes an image forming unit, an image reading unit, an image inspecting unit and a history generating unit. The image forming unit forms an image on a sheet. The image reading unit reads a sheet face on which the image is formed, thereby generating a scan image. The image inspecting unit compares the generated scan image with a normal image to detect an error in the scan image. When the image inspecting unit detects the error, the history generating unit generates detection information on the detected error and embeds the generated detection information in the scan image, thereby generating a history image.