An authentication system includes a plurality of authentication apparatuses, each of which includes first biological information of a same set of users; a crosschecking unit for crosschecking input biological information with a part of the first biological information; a transmitter for assigning second biological information included in the first biological information other than the part of the first biological information to the other authentication apparatuses without assigning same information in the second biological information to other authentication apparatuses, and to request the other authentication apparatuses to crosscheck the input biological information with the assigned second biological information; and a receiver for receiving, from the one or more other authentication apparatuses, one or more results of crosschecking the input biological information with the assigned second biological information by the one or more other authentication apparatuses in response to the requesting.