An original stream file and an after-recording data file are managed as different files. In the original stream file, data is made up of sets of partial data (CU) divided in accordance with a predetermined interval. Likewise, in the after-recording data file, data is made up of sets of partial data (CA) divided in accordance with a predetermined interval. These sets of data are recorded onto a disc such that the after-recorded data (CA) is recorded in a region adjacent to a relevant original stream (CU). This allows reproduction and real-time after-recording with the use of a general MPEG-2 PS/TS decoder. Moreover, this allows realization of data recording that causes less interruption of reproduction when non-destructive editing is carried out with respect to an after-recorded result.