A gateway device includes a base processor which converts a signal input from an IP network to a signal which can be handled by the gateway device, and a home appliance control processor having a controller which converts the signal which can be handled by the gateway device to a control signal in compliance with the communications protocol of a home appliance to be controlled. The controller stores, on a table, information about the communications protocol, driver, controllable setting condition and status of respective appliances to be controlled in association with each other. The controller also includes a conversion functional block which converts information supplied to the control information of the communications protocol of the respective appliances to be controlled on the basis of the stored information.