An image reading apparatus includes a document table, a first generating section, a first assigning section, a second generating section, a second assigning section, and a relating section. The first generating section generates a plurality of first image data pieces representing respective first side images of a plurality of documents. The first assigning section assigns first symbols to the respective first image data pieces based on a reference position of the document table. The second generating section generates a plurality of second image data pieces representing respective second side images of the plurality of documents. The second assigning section assigns second symbols to the respective second image data pieces based on the reference position. The relating section relates the first image data pieces to the respective second image data pieces based on the first symbols and the second symbols.