PURPOSE: To improve the transfer efficiency between network connectors in a network in which plural sub network used for communication with a connectionless type packet are connected via the network connectors.

CONSTITUTION: A data part of a received packet is used for one data unit without decomposing the structure of the data part of a packet when a packet length of a packet from a bus network B received by a network connector 8 is smaller than the maximum packet length of a sender side sub network C and a succeeding destination is other network connector 9 in the sub network C. That is, the data are subjected to capsule processing. Then some data subjected to capsule processing are integrated and transferred in one packet.