PURPOSE: To facilitate editing operation at the time of component addition, deletion, or alteration in a generated component table.

CONSTITUTION: When a component is newly added to the component table 15, the system is set to the editing mode of a property window 13, and component information is newly registered into the property window 13. When this information is added to a component information storage part, contents of a component table element storage part are altered associatively. Consequently, the component table 15 is extended upward by one field and one component is added to the component table 15 of which contents are altered.