To greatly improve the convenience of using electronic authenticating technology and an electronic certificate used for identification in an e-market place rapidly evolving based upon the Internet.

A one-stop service system for electronic authentication wherein a plurality of authentication stations and a mutual authentication service server are connected is equipped with a means which inquires validity of an authentication station being the issue source of a certificate at a request to inquire the certificate from one of the authentication stations and a means which answers the result of the inquiry to the authentication station having made the request.