There is provided a communication apparatus including a reference electrode; a signal electrode which electrostatically couples to a communication medium; a measurement unit for measuring an impedance of a circuit system including between the reference electrode and the signal electrode; and a transmission processing unit for creating a potential difference between the signal electrode and the reference electrode based on a transmission power corresponding to the impedance of the circuit system measured by the measurement unit, and transmitting a signal to another communication apparatus electrostatically coupled to the communication medium.