Specific characteristics of a branch structure between a behavioral description and a hardware description, a structural dependence relation therebetween, and the like are extracted and used to shorten the time of processing for equivalence checking, thereby contributing to the shortening of a processing time required for equivalence checking for a high-level description and a behavioral synthesis result. Upon checking of the equivalence of a high-level description and a synthesis result obtained by performing a behavior synthesis on the high-level description according to a behavioral synthesis restriction, correspondence information between flip-flops with a feedback loop in the synthesis result and variables associated therewith with a backward data dependence relation in a high-level description is generated and used.