PURPOSE: To check the design data independent of a printed circuit board CAD by providing a rule definition part performing the definition, addition, and update of the rule necessary for the data check of the printed circuit board by a designer by himself in a data check module.

CONSTITUTION: An operator defines the general-purpose and changeable rules like a rule description table 23 by using a user interface 9. The defined rule is stored in a rule base 7 by a rule base management part 6. When checking the design data, the operator prepares an intermediate file by using data convert modules 2a-2n corresponding to respective printed circuit board CAD 1a-1n to command the execution of the data check to a rule process part 8 by using the user interface 9. Thus, there is an effect to support the high-quality design.