An image forming apparatus comprises a document reading unit for reading a document on a table or at a predetermined reading position to which the document is transported by a document feeder and an interrupt key for receiving an interrupt job. When a user turns on the interrupt key, an inquiry whether a document for an interrupt job is read on a table or at a predetermined reading position to which the document is transported by the document feeder is displayed on a liquid crystal display. When the user selects either one of them, an interrupt process is executed.