An image forming apparatus includes an image forming unit including a scanner and a printer, a server, and a local network circuit connecting the image forming unit and the server. In each of the image forming unit and the server, a hardware processor selects one of a first communication protocol and a second communication protocol in accordance with data to be transmitted by a transceiver. The first communication protocol includes a provision for ensuring reliability of communication, and the second communication protocol does not include a provision for ensuring reliability of communication.