To solve the problem that much labor is required in the case of constructing a network.

In this network constructing system, the list of parts capable of combination is specified and stored on a database, the network is designed by selecting parts out of the list of parts in the case of meeting, the preparation statement of combination is prepared, operation is verified by really assembling the designed combination, the combination is disassembled and delivered after verification and the combination is assembled on the construction site. At the time of assembling the network on the construction site, since the operation of the network is confirmed, it is not necessary to perform control such as operation verification on the construction site and it is not necessary to dispatch the talent of high technological ability to the construction site of the network, either. Therefore, labor is reduced when the network is contructed.