File systems of a plurality of service providers are allocated in a single memory area so that the service providers share a single information recording medium.In an initial state, an IC card issuer manages the entire memory area. When a different service provider separates the memory area to generate a new file system, the service provider is required for the authority of separating the memory area and authentication by the IC card issuer. After the file is separated, in order to access the file system, authentication by the service provider which has separated the file is required. The IC card provides a user with ease of use as if the IC card were directly issued by the service provider of the service that the user is currently using.