A gateway device that relays between a first communication network and a plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45), the gateway device comprising: a plurality of control units (341∼381) corresponding to the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45); and a data analysis and management unit corresponding to the first communication network, the plurality of control units (341∼381) being configured to respectively transmit first data received from the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45) to the data analysis and management unit and transmit second data received from the data analysis and management unit to the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45); and the data analysis and management unit being configured to: analyze data received from the first communication network and transmit a result of the analysis as the second data to a control unit (341∼381) included in the plurality of control units (341∼381), the control unit (341∼381) being related to result of the analysis, analyze the first data received from the plurality of control units (341∼381) respectively and transmit a result of the analysis to the first communication network, and generate a plurality of local MAC addresses from a MAC address given to the gateway device and assign the local MAC addresses to the plurality of control units (341∼381) based on a management table, wherein the data analysis and management unit holds the management table connecting an equipment number for identifying the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45), the plurality of local MAC addresses, and classifications of the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45). a plurality of control units (341∼381) corresponding to the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45); and a data analysis and management unit corresponding to the first communication network, the plurality of control units (341∼381) being configured to respectively transmit first data received from the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45) to the data analysis and management unit and transmit second data received from the data analysis and management unit to the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45); and the data analysis and management unit being configured to: analyze data received from the first communication network and transmit a result of the analysis as the second data to a control unit (341∼381) included in the plurality of control units (341∼381), the control unit (341∼381) being related to result of the analysis, analyze the first data received from the plurality of control units (341∼381) respectively and transmit a result of the analysis to the first communication network, and generate a plurality of local MAC addresses from a MAC address given to the gateway device and assign the local MAC addresses to the plurality of control units (341∼381) based on a management table, wherein the data analysis and management unit holds the management table connecting an equipment number for identifying the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45), the plurality of local MAC addresses, and classifications of the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45). analyze data received from the first communication network and transmit a result of the analysis as the second data to a control unit (341∼381) included in the plurality of control units (341∼381), the control unit (341∼381) being related to result of the analysis, analyze the first data received from the plurality of control units (341∼381) respectively and transmit a result of the analysis to the first communication network, and generate a plurality of local MAC addresses from a MAC address given to the gateway device and assign the local MAC addresses to the plurality of control units (341∼381) based on a management table, wherein the data analysis and management unit holds the management table connecting an equipment number for identifying the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45), the plurality of local MAC addresses, and classifications of the plurality of communication devices (41, 42) or/and second communication networks (43, 44, 45).