Description of works such as “requirement”, “definition”, and “confirmation” in the narrow sense in a design process is made possible. A design work recording unit (22a) records in a data storage device (6) an inputted “design work name” as one of “external requirement name”, “concept definition name”, “internal requirement name”, “detailed definition name”, and so on. An inter-work relation recording unit (22b) records in the data storage device (6) a relation between two “design work names” selected from “external requirement name”, “concept definition name”, “internal requirement name”, “detailed definition name”, and so on recorded in the data storage device (6). Here, the inter-work relation recording unit (22b) records a relation between “external requirement name” and “concept definition name”, a relation between “concept definition name” and “internal requirement name”, a relation between “internal requirement name” and “detailed definition name”, and so on.