PURPOSE: To implement parallel connection of connection path information for plural buses by a network management system without any error.

CONSTITUTION: A network management system 61 publicates a command for connection path collection to a bus connection processing section PTM 5 of a bus terminator in which buses 81-84 are terminated. In this case, an ID of the network management system 61 and a command ID are added as parameters. The bus connection processing section PTM 5 brings a fixed pattern of a connection path information collection command transmission area into a collection command pattern for the collection of connection path information, sets the command ID into a command ID received from the network management system 61 and sets a destination system ID into an ID of the network management system 61 for the transmission. A bus connection processing section PTM 57 of the other terminator of the bus adds the command ID to the connection path information collected by a bus ID transfer area and sends the resulting information to the network management system 61 designated by the destination system ID.