In goods genuineness/counterfeit discrimination using IC tags, contradictory problems of the reliability and lifetime of the IC tags and the accuracy of goods genuineness/counterfeit discrimination are solved and circulation of goods mounted with defective IC tags is prevented. A ratio of a number of IC tags having sent information indicative of the fact that the IC tags are mounted on the same object member to a number of IC tags from which the information is to be sent originally is determined and the genuineness/counterfeit discrimination is performed with the ratio. With regard to adopting a combination of genuineness/counterfeit discrimination, information necessary for detection is added to goods and information of the inspection area is stored in the IC tags. When the number of defective IC tags is large, goods mounted with the IC tags is collected.