An image forming apparatus includes: an internal storage device; an attachment portion to which an external storage device can be attached; an image reading unit that reads contents of an original as an image and converts the image into an electronic signal; a first image processing unit that generates image data from the electronic signal; and a second image processing unit that separates the image data thus generated into character data that is recognized as characters and data that is recognized as different data from the character data and, when the external storage device is attached to the attachment portion, stores data composed of an entirety or a part of the character data that is recognized as characters as first data in the external storage device and the data that is recognized as different data from the character data as second data in the internal storage device.