A communication device includes a plurality of packet processing modules in which a packet processing function is changeable with a program, and a management server holds program information of a plurality of different packet processing module circuits settable to the packet processing modules, selects the packet processing module circuit to be set to the packet processing module, of the plurality of different packet processing module circuits, and transmits the program information of the selected packet processing module circuit and information for identifying the packet processing module that is an object to be set, to the communication device that is an object to be set.