The directory information on a file system recorded on an optical disc is cached onto a hard disk as a directory table. When accessing a file on the optical disc, a processor references the directory table so as to obtain information related to a position, on the disc medium, where the file to be accessed is located, without accessing the directory information on the optical disc. A disc I/O controller moves a pickup unit to the location indicated by the positional information on the file to be accessed and reads the data on the file. The pickup unit is used to detect signals from the optical disc.