Attachment of a USB memory is sensed and whether the USB memory can be recognized or not is determined based on data information output from the USB memory. When the USB memory cannot be recognized, an emulation transition screen is displayed. Thereafter, when an instruction to start transition to an emulation mode is given, an emulation mode transition instruction signal and an IP address of an MFP on a network are output. Receiving the input of the emulation mode transition instruction signal, an emulation mode start-up/end unit starts up the emulation mode.