To provide an authentication device, capable of further surely preventing unauthorized use of resources by an unauthorized user having no use authority.

Whether user information for identifying a user is matched or not is determined by collation (steps S1-S3), and whether manager information for identifying a manager is matched or not is determined by collation (steps S4-S6), and when both the collation results are determined to be matched (YES in step S6), the use of resources is permitted in step S7.