A flexible flat cable includes a plurality of ground lines and a plurality of signal lines. Each of the ground lines is connected to an electromagnetic shield layer by two connection line members. An arrangement of the ground lines and signal lines that are positioned in a region on one side of a center line of the flexible flat cable and an arrangement of the ground lines and signal lines on a region on the other side are symmetric with respect to the center line. In each of two connectors to which end portions of the flexible flat cable are coupled, terminals corresponding to the ground lines are grounded, a terminal corresponding to a signal line interposed between two ground lines is assigned a high-speed signal, and a terminal corresponding to another signal line is assigned a ground potential.