In a system of manufacturing a semiconductor integrated circuit, a client, a data-managing center, a designing center, and a manufacturing center are connected together via the Internet. The data-managing center has a cost/number-of-days database, a reservation status database, and a design/manufacture status database. Each of the centers uses information contained in the databases of the data-managing center, performs two-way communication with the client, and thereby progresses the production of the semiconductor integrated circuit.