An image forming apparatus includes a CPU. According to user operations, the CPU causes an image reading unit to read, at once, the front surfaces of documents placed on the respective area divisions of a document platen, and obtains individual front surface images. The CPU causes the image reading unit to read the back surfaces of the documents at once, and obtains individual back surface images. The CPU generates image files, each including a front surface image and a back surface image, for the respective area divisions. The CPU determines whether or not a read error is present in each of the obtained images. When an image file includes an image having a read error, the CPU stores, in an HDD, the image file with a file name indicating presence of a read error.