A DVD recorder is provided in which access control is effected by a driver layer (41), a UDF file system layer (42,) that reads and writes data from and to a DVD-RW with reference to a file system, and a data base layer (43) that accesses the UDF file system layer (42) with reference to content management information for management of contents stored in the DVD-RW. The data base layer (43) reads TMP_VMGI which is intermediate-state management information for the DVD-RW, and provisionally registers a file system into the UDF file system layer (42) with reference to information included in the TMP_VMGI. Thus, a file system is provisionally formed even if the DVD-RW loaded in the DVD recorder is in the intermediate state having no file system recorded therein.