PURPOSE: To facilitate complicated decision and to perform decision based on a condition which is not prepared at first by taking out an operation assent parameter from file data and deciding whether an operation request should be accepted or not in accordance with its presence or absence.

CONSTITUTION: An item of design review (as decision information) as information for generation progress of data is added to this data related to design. When an operation request is inputted from an input device 2, a controller 1 extracts information of operation progress from data on a memory 4 and decides whether the item of review (operation assent parameter) exists in this information or not, and a requested operation is executed if review is not performed yet, but a message of operation reject is outputted through an output device 3 if it is already performed. Thus, complicated assent management is performed though information for required assent management is not preliminarily prepared.