An image reading device which reads an image to obtain an image signal includes: a scanning unit; a chassis member; a control unit provided in a position which does not move together with the scanning unit; and a flexible flat cable which connects the scanning unit to the control unit, includes one end attached to a side of the chassis member and a position other than the one end fixed to a position which does not move with the scanning unit, includes a range closer to the one end than the fixed position parallel to a moving direction of the scanning unit, and is arranged to extend from the one end to one side, be bent into a U-shape, enter between the scanning unit and the chassis member, and reach the fixed position, and the flexible flat cable includes a transmitting layer, a shielding layer, and a stress adjusting layer.