A wireless communication system includes a first differential signal line, a differential coupler, and an electronic circuit. The differential coupler has a second differential signal line to perform wireless communication of a differential signal with the first differential signal line via electromagnetic field coupling. The electronic circuit is connected to the differential coupler via a wired transmission path to process the differential signal. A surface of a board or a ground pattern of the electronic circuit is inclined or upright with respect to the second differential signal line so as to separate away from a direction in which the first differential signal line extends.