An aircraft communication system of an aircraft on which a plurality of devices are mounted, the aircraft communication system being configured to perform communication between the respective devices, wherein the plurality of devices have different degrees of redundancy, the aircraft communication system comprises a plurality of communication processing units provided corresponding to the plurality of devices; and a plurality of communication lines connecting between the respective communication processing units according to the degree of redundancy of the devices to which the communication processing units are connected, wherein: a number of the communication lines connected to each of the plurality of communication processing units differs depending on the degree of redundancy of the corresponding device, the plurality of communication processing units are able to perform bidirectional communication via the plurality of communication lines, and each of the plurality of communication processing units is configured to process a plurality of pieces of communication data received from the plurality of communication lines connected according to the degree of redundancy, and generate a plurality of pieces of the communication data corresponding to the plurality of communication lines connected according to the degree of redundancy, and determine whether the plurality of pieces of received communication data are to be acquired based on identification information included in the plurality of pieces of received communication data, and acquire the communication data determined to be acquired. a plurality of communication processing units provided corresponding to the plurality of devices; and a plurality of communication lines connecting between the respective communication processing units according to the degree of redundancy of the devices to which the communication processing units are connected, wherein: a number of the communication lines connected to each of the plurality of communication processing units differs depending on the degree of redundancy of the corresponding device, the plurality of communication processing units are able to perform bidirectional communication via the plurality of communication lines, and each of the plurality of communication processing units is configured to process a plurality of pieces of communication data received from the plurality of communication lines connected according to the degree of redundancy, and generate a plurality of pieces of the communication data corresponding to the plurality of communication lines connected according to the degree of redundancy, and determine whether the plurality of pieces of received communication data are to be acquired based on identification information included in the plurality of pieces of received communication data, and acquire the communication data determined to be acquired. a number of the communication lines connected to each of the plurality of communication processing units differs depending on the degree of redundancy of the corresponding device, the plurality of communication processing units are able to perform bidirectional communication via the plurality of communication lines, and each of the plurality of communication processing units is configured to process a plurality of pieces of communication data received from the plurality of communication lines connected according to the degree of redundancy, and generate a plurality of pieces of the communication data corresponding to the plurality of communication lines connected according to the degree of redundancy, and determine whether the plurality of pieces of received communication data are to be acquired based on identification information included in the plurality of pieces of received communication data, and acquire the communication data determined to be acquired. process a plurality of pieces of communication data received from the plurality of communication lines connected according to the degree of redundancy, and generate a plurality of pieces of the communication data corresponding to the plurality of communication lines connected according to the degree of redundancy, and determine whether the plurality of pieces of received communication data are to be acquired based on identification information included in the plurality of pieces of received communication data, and acquire the communication data determined to be acquired.