To provide a collaborative design supporting device and a method therefor capable of performing a customized flow control for every person.

A process designing program 20 is composed of the database for receiving the data necessary for this collaborative design supporting method, and storing and managing the data, a database managing part 202 for managing the database 200, a summing-up part 204 receiving the input from persons concerned from a PC1 and summing up the same, a condition management part 206 for managing a condition of the discussion, and a BBS part 208 for providing a BBS (bulletin board system) function. The process designing program 20 displays one or more discussion subjects, and displays the message to the display by a BBS method. When a ratio of agreement to any discussion object is over a standard, the process designing can be transferred to the next phase to advance the discussion.