A management system for a recording medium recorded with a multimedia data stream wherein in a first data made up of video and sound, an amount of data for a predetermined playback period is managed as a first unit (EU), an individually reproducible minimum unit of data in the first unit (EU) is managed as a second unit (VU), each of the first units (EUs) is adapted to have an equal period of playback time to others, and each of the second units (VUs) is adapted to have an equal period of playback time to others. In this management system, the positional information of the second unit (VU) on the recording medium is held as management information for every second unit, so that the positional information of the first unit (EU) on the recording medium is calculated based on the positional information of the second unit (VU) on the recording medium.