Abstract: An inter-LAN connection apparatus and a method for increasing the speed of communication and to expand the network. The inter-LAN connection apparatus has a plurality of ports corresponding to a plurality of LANs, respectively, and a common unit that is commonly connected to the ports. Each of the ports receives a frame supplied from the corresponding LAN, aborts the frame when the destination picked up from the received frame exists in the LAN that is the source of transmission, transfers the frame to the common unit when the destination exists in the LAN different from the LAN that is the source of transmission, and sends the frame transferred from the common unit to the LAN via a corresponding port.