PURPOSE: To produce the highly reliable network control information without giving any burden to a worker in a network control information production system which produces the network control information that is used by a network control program which controls the logical connection, disconnection, etc., of networks.

CONSTITUTION: A network control information extracting means 11 reads the on-line environment defining information 21 to define an operating environment of an on-line program and extracts the network information 411 on the network constitution. An operating condition information input means 12 requests the input of the operating condition information 412 which shows the operating conditions of a network control program. A network control information production means 13 produces the network control information 31 based on the information 411 and the information 412 which is inputted from a terminal equipment 5 in response to the input request of the means 12.