An information processing apparatus is configured to authenticate a user. In one embodiment, the information processing apparatus includes a storage unit that stores user identification information in association with user authentication information. Identification information for identifying a user is inputted into the apparatus. If the inputted identification information matches the stored user identification information, the apparatus selects the user authentication information associated with the user identification information that matches the inputted identification information, and sends the selected user authentication information to an authentication server, so that authentication is executed. If the inputted identification information does not match the stored user identification information, the apparatus requires that authentication information be provided by the user. In this case, the apparatus sends the inputted user authentication information to the authentication server, so that authentication is executed; and upon authentication, the apparatus stores the inputted user identification information in association with the inputted user authentication information.