The communication apparatus includes: a first circuit board unit including, on a front surface of the communication apparatus, a port for transmitting and receiving data to and from the network; a second circuit board unit including a plurality of first connectors connected to at least one of the first circuit board units, a second connector being capable of accommodating at least a bandwidth accommodated by the plurality of first circuit board units, and being connected, via a cable, to the other communication apparatus of a standby system; and a cross bar switch for selectively outputting data to the first connectors or the second connector as a data output destination, and a ventilation control unit for controlling a flow of air flowing between each of the first circuit board unit and the second circuit board unit, and outside of the communication apparatus.