A communication system includes a transmitter including a transmitting circuit to generate radio frequency signals for transmitting data and an electrical field coupling antenna to transmit the radio frequency signals as an electrostatic field or an inductive electrical field; and a receiver including an electrical field coupling antenna and a receiving circuit to perform a reception process on radio frequency signals received by the electrical field coupling antenna. Each of the electrical field coupling antennas of the transmitter and the receiver includes a coupling electrode, a resonant portion to strengthen electrical coupling between the coupling electrodes, and a radio wave absorber placed near the coupling electrode. The radio frequency signals are transmitted through electrical field coupling between the electrical field coupling antennas facing each other of the transmitter and the receiver.