An image forming apparatus includes a reading unit which reads a document image, a detecting unit which detects a document direction representing whether a sub-scanning direction in reading the document image is a short side or a long side direction of an original document, a designating unit which designates, as a copying function, a form for copying the document image on a sheet, an editing unit which edits the read document image as an image corresponding to the designated copying function, a copying unit which copy the edited image on the sheet, and an acquiring unit which acquires a sheet direction representing whether a conveying direction of the sheet conveyed to the copying unit is the short side or the long side direction of the sheet. The editing unit executes processing on the document image on the basis of the document direction, the sheet direction, and the designated copying function.