An image forming apparatus includes a control board, a first connection terminal provided on an outer surface of the control board, an installation section disposed at the outer surface side of the control board, a substrate capable of being installed into the installation section, a second connection terminal provided on a first surface of the substrate and connected to the first connection terminal, a grip portion provided on a second surface of the substrate at a first end thereof in an in-plane direction, and an external connection terminal provided on the substrate so as to project from the substrate at a second end thereof in the in-plane direction. The external connection terminal is externally exposed to allow an external device to be connected thereto when the substrate is installed into the installation section after the external connection terminal is inserted through an opening in the apparatus body.