Rencently, a designer demands the design supporting system with management of design knowledge. Although the definition and modeling of knowledge are very difficult, it is important to manage the past design process and the past product information. Authors have been developing the top down oriented design system that supports design from the concept design to the detailed design. In this system, the network model of entities and attributes, that express the product information, is grown up in proportion as stepwise design. This paper proposes the framework for the use of information on the past design process and product in this system. The system functions of copying the partial network and joining it with other networks are represented as managing of the design knowledge.