An image forming apparatus main body (apparatus main body) and an automatic document feeder mounted on the apparatus main body are provided, and a cable-side connector provided at a front end of an electrical cable extending from the automatic document feeder is removably connected to a board-side connector provided on a circuit board of the apparatus main body. In this configuration, an opening portion is provided in a back face of a housing of the apparatus main body at a position opposing the board-side connector, a lid that covers this opening portion is attached to a front end portion of the electrical cable by an attachment member, and this lid is configured so as to be attachable to the opening portion by a hook and fixing by screwing by means of a screw insertion boss.