To hide a connector for electrical connection with a paper discharge processing device equipped to the body of an image forming device from the appearance, without having to use extra parts, and to improve the user's operability by lowering the height of the body of the image forming device.

The body of the image forming device to which a paper discharge processing device can be connected is so constituted that a connector for electrical connection with the paper discharge processing device, equipped to the body of the image forming device, is hidden by an auxiliary paper discharge tray equipped to the body of the image forming device for improving paper discharge alignment performance, when the paper discharge processing device is not to be mounted; and when the paper discharge processing device is mounted, the auxiliary paper discharge tray is removed.