A communication apparatus includes a communication board provided with a Power Line Communication (PLC) signal processor so as to be used in common in other apparatuses. The communication apparatus performs communication through a power line and a transmission medium different from the power line. The communication apparatus includes a power board that is provided with a power supply connected to the power line, an interface board that is separately formed from the power board and is provided with an interface for performing communication through the transmission medium, and a communication board that is separately formed from the power board and the interface board. The communication board is provided with a power line communicator for performing communication through the power line and a connector electrically connectable to the power board and the interface board.