An information serving system that includes an information device capable of setting a user identifier carrying a medium type indicating an information type the information device is compatible with and identifying an information-provided user and also capable of connection to a network. An information serving device to which the information device is connected via the network, the information serving device includes databases having recorded therein, in association with each other, user profile data indicating information to be provided correspondingly to a user identifier, and content data associated with a medium type and information genre, respectively, and a request handling computer which searches, upon request from the information device, the database for content data to acquire the content data and supplies the information device with the content data as a one of the medium type the information device is compatible with.