The production system called "SYMPHONY" based on a bridge model was developed jointly by six companies in the bridge manufacturing industry and has been put into practical use. The production model can accommodate diversified bridge types and is compatible with the construction CALS (Continuous Acquisition and Life-cycle Support). The system will change the conventional way of bridge building. SYMPHONY is basically a combined system of a commercial 3-dimensional CAD and a database. By incorporating the jointly developed tool, the system efficiently creates a product model. In reality, this is an integrated system that provides its peripheral subsystems with data of the product model. This paper reports the features and the effect of its introduction and discusses the production system derived from the 3-dimensional product model.