A communication terminal is provided with: first and second transmission units transmitting signals on a communication line, first and second receiving units receiving signals from another communication terminal; and a communication method switching unit switching the signal communication method. The first transmission unit transmits an electrical current signal to the communication line. The first receiving unit receives a voltage signal obtained by converting, by means of a current/voltage conversion unit, the electrical current signal transmitted from the first transmission unit. The second transmission unit transmits a communication signal to the communication line as a voltage signal. The second receiving unit receives the voltage signal transmitted from the second transmission unit. The communication method switching unit switches between an electrical current transmission method in which transmission is performed by the first transmission unit, and a voltage transmission method in which transmission is performed by the second transmission unit.