A device comprising: a first unit; and a second unit, the first unit including: a function provider that provides a predetermined function; a first storage controller that stores in a first storage authentication information used for user authentication; and a provision controller that controls the function provider to provide the predetermined function when a user authentication result indicating an authorized user is obtained; and the second unit including: a first acquirer that acquires the authentication information before performance of the user authentication; a second storage controller that stores the acquired authentication information in a second storage; a first generator that generates priority user information and stores the priority user information in the second storage, the priority user information representing, of the acquired authentication information, authentication information corresponding to a user who has been authenticated in user authentication as an authorized user, to which time information of the latest successful authentication is added; a second acquirer that acquires input authentication information that is input for user authentication; and an authenticator that performs user authentication by collating the input authentication information with the priority user information stored in the second storage and supplies the provision controller of the first unit with a user authentication result. a first unit; and a second unit, the first unit including: a function provider that provides a predetermined function; a first storage controller that stores in a first storage authentication information used for user authentication; and a provision controller that controls the function provider to provide the predetermined function when a user authentication result indicating an authorized user is obtained; and a function provider that provides a predetermined function; a first storage controller that stores in a first storage authentication information used for user authentication; and a provision controller that controls the function provider to provide the predetermined function when a user authentication result indicating an authorized user is obtained; and the second unit including: a first acquirer that acquires the authentication information before performance of the user authentication; a second storage controller that stores the acquired authentication information in a second storage; a first generator that generates priority user information and stores the priority user information in the second storage, the priority user information representing, of the acquired authentication information, authentication information corresponding to a user who has been authenticated in user authentication as an authorized user, to which time information of the latest successful authentication is added; a second acquirer that acquires input authentication information that is input for user authentication; and an authenticator that performs user authentication by collating the input authentication information with the priority user information stored in the second storage and supplies the provision controller of the first unit with a user authentication result. a first acquirer that acquires the authentication information before performance of the user authentication; a second storage controller that stores the acquired authentication information in a second storage; a first generator that generates priority user information and stores the priority user information in the second storage, the priority user information representing, of the acquired authentication information, authentication information corresponding to a user who has been authenticated in user authentication as an authorized user, to which time information of the latest successful authentication is added; a second acquirer that acquires input authentication information that is input for user authentication; and an authenticator that performs user authentication by collating the input authentication information with the priority user information stored in the second storage and supplies the provision controller of the first unit with a user authentication result.