A communication device (10) includes a communication IF (11) transmits and receives, in a layer 2, a packet having a structure that does not include a MAC address; a TCP/IP processing unit (12) transmits and receives a packet in a TCP/IP layer; and a switch (13) performs processing on the packet received by the communication IF (11) and the TCP/IP processing unit (12). When the switch (13) performs processing for transmitting, from the TCP/IP processing unit (12), the packet received by the communication IF (11), a pseudo MAC header is added to the packet and the packet is output to the TCP/IP processing unit (12). When the switch (13) performs processing for transmitting, from the communication IF (11), the packet received by the TCP/IP processing unit (12), the pseudo MAC header is deleted from the packet and the packet is output to the communication IF (11).