Communication system and the receiving apparatus used for the same

A communication system is provided comprising a living body-side electrode which primarily capacitively couples with a living body, an environment-side electrode which primarily capacitively couples with an external environment, and a circuit board on which a circuit which processes a signal which is output from at least one of the living body-side electrode and the environment-side electrode is mounted, wherein the circuit board is not placed between the living body-side electrode and the environment-side electrode.