Before each content file is recorded first to a recording medium, a flag indicating a recording state of a content file is generated corresponding to a physical area where an index file can be continuously recorded. An index file is generated which associates attribute information with the generated flag added thereto with real data of each content file, and the generated index file is recorded to the recording medium. Since fragmentation of the physical area where the index file is recorded is restrained to a minimum level, a high-speed reading operation is realized.