The present invention is an authentication method for disclosing identification data of an object and authenticating when referring to data of the object corresponding to the identification data based on the identification data and can associate a tag device and data of a referring entity and authenticate that data of the tag device is referred by a proper referring entity by generating a third value by conducting a predetermined calculation with a temporary first value indicating a most recent referral to the identification data of the object and a temporary reference second value issued to a referring entity of the identification data for each referral, and authenticating a relationship between the object and the referring entity by verifying the third value.