There is provided person oneself authenticating means for authentication of a user, which is mainly used for person oneself authentication in Internet banking or the like and is high in security, and is realizable by functions ordinarily provided in a PC, a mobile phone, or the like, the authenticating means being less in burden required for user authentication key management and authentication operations. Sound or an image is adopted as an authentication key for person oneself authentication. Authentication data is edited by combining an authentication key, which is selected by a registered user, and sound or an image that is other than the authentication key, and the authentication data is continuously reproduced in a user terminal. A time in which a user has discriminated the authentication key from the reproduced audio or video is compared with a time in which the authentication key should normally be discriminated, which is specified from the authentication data. When both times agree, the user is authenticated as a registered user.