There is provided an image forming device comprising a connection unit to which an external device is detachably attached, a reading unit to read an image from an original to generate image data; an image forming unit to form an image; a controller that executes a plurality of modes including a scan-to-memory mode where image data is obtained through the reading unit and the obtained image data is stored in the external memory and a direct print mode where an image corresponding to image data stored in the external memory is formed, and a storage unit to store mode information concerning at least one mode, the at least one mode having been executed by the controller with respect to the external memory. The controller executes a mode stored in the storage unit as the mode information in response to connection of the external memory to the connection unit.