The present invention is concerned with a data management apparatus, in which data recorded by dubbing from a CD-DA (Compact Disc Digital Audio) to a hard disc drive (HDD) (31) as a second recording medium are supervised by a hard disc recording and/or reproducing unit (3), which hard disc recording and/or reproducing unit (3) supervises the identification information of the CD-DA to enable the supplementary information to be obtained via communication means from a network server, and in which the so produced supplementary information is automatically registered in the hard disc recording and/or reproducing unit (3) to permit the supplementary information, such as the name of music airs, to be produced even in the absence of a user's input.