A communication apparatus (300; 300-2) adapted for a real-time system, the communication apparatus (300; 300-2) comprising: a plurality of virtual machines; a storage unit that includes a multicast storage area specified for each multicast group and storing a multicast frame addressed to virtual machines belonging to the multicast group; and a transfer control unit, wherein the transfer control unit comprises: a transfer unit (22; 106) configured to write the multicast frame into a multicast transfer virtual storage area mapped to the multicast storage area; a storage control unit (24, 141) configured to map a multicast reception virtual storage area to the multicast storage area when an entry of a multicast frame is registered in transfer destination information; and a descriptor output unit configured to output a descriptor of the multicast frame to the virtual machines belonging to the multicast group, and each of the virtual machines comprises: a descriptor receiving unit (11; 64) configured to receive the descriptor, and a reading unit (14; 63) configured to read the multicast frame from the multicast reception virtual storage area mapped to the multicast storage area specified based on the descriptor when the descriptor is received by the descriptor receiving unit (11; 64). a plurality of virtual machines; a storage unit that includes a multicast storage area specified for each multicast group and storing a multicast frame addressed to virtual machines belonging to the multicast group; and a transfer control unit, wherein the transfer control unit comprises: a transfer unit (22; 106) configured to write the multicast frame into a multicast transfer virtual storage area mapped to the multicast storage area; a storage control unit (24, 141) configured to map a multicast reception virtual storage area to the multicast storage area when an entry of a multicast frame is registered in transfer destination information; and a descriptor output unit configured to output a descriptor of the multicast frame to the virtual machines belonging to the multicast group, and a transfer unit (22; 106) configured to write the multicast frame into a multicast transfer virtual storage area mapped to the multicast storage area; a storage control unit (24, 141) configured to map a multicast reception virtual storage area to the multicast storage area when an entry of a multicast frame is registered in transfer destination information; and a descriptor output unit configured to output a descriptor of the multicast frame to the virtual machines belonging to the multicast group, and each of the virtual machines comprises: a descriptor receiving unit (11; 64) configured to receive the descriptor, and a reading unit (14; 63) configured to read the multicast frame from the multicast reception virtual storage area mapped to the multicast storage area specified based on the descriptor when the descriptor is received by the descriptor receiving unit (11; 64). a descriptor receiving unit (11; 64) configured to receive the descriptor, and a reading unit (14; 63) configured to read the multicast frame from the multicast reception virtual storage area mapped to the multicast storage area specified based on the descriptor when the descriptor is received by the descriptor receiving unit (11; 64).