A terminal sends to a host computer CAD drawing data which contains basic specifications of products ordered by a customer. The host computer manages product catalog information including price information of products for which orders can be accepted and customer planning information in which planning information of each customer about detail specifications of products has been registered, receives the CAD drawing data sent from the terminal, extracts the basic specifications of the ordered products from the CAD drawing data, searches the product catalog information using the extracted basic specifications of the ordered products and the customer planning information, creates quotation data based on retrieved product catalog information, and sends the quotation data to the terminal.