An integrated gateway apparatus includes a policy storage for storing therein a first information on message filtering and switching policies for messages received from heterogeneous devices in lower networks via network interfaces; a device management unit for extracting a second information on the messages, the devices and the network interfaces; a layer-basis filter unit for performing, based on the first and the second information, the message filtering and switching on the messages on a layer basis; and an integrated switch management unit for providing the first information to the layer-basis filter unit and controlling the layer-basis filtering unit. The layer-basis filter unit includes a switch filter unit, a route filter unit and a gateway filter unit for performing the message filtering and switching in a MAC layer, in a network layer and a transport layer and in an application layer, respectively.