To maintain the consistency of product information having a three- dimensional model 4, a drawing 5 and item field data 15.
When access requests are made to any of the three-dimensional model 4, the drawing 5 corresponded to the model 4 and the item field data 15 for design, a controlling part accepts one access request and performs processing that inhibits the other access requests from accessing the three- dimensional model 4, the drawing 5 and the item field data 15 in order to connect an MDM system for managing the three-dimensional model 4 showing a three-dimensional structure composed of one or more parts and the two-dimensional drawing 5 corresponding to the three-dimensional model 4 to a PDM system for managing information about one or more parts of the three- dimensional model 4 as the item field data 15 and to perform design processing while maintaining the consistency of objects (three-dimensional model 4, drawing 5 and item field data 15).