OPTICAL DISK FILING DEVICE

PURPOSE:To easily form a list and to easily execute additional writing to the list based on a corresponding state to user data by recording the user data in a file recording area in a user recording area in the units of files and recording index data corresponding to the user data in an index recording area at every file. CONSTITUTION:A substitutive track area 30 and a user entry area 40 are provided between guard tracks at the inner side and the outer side of a prescribed track out of the tracks of the title optical disk filing device. Further, the user area 40 is partitioned into an index recording area 41 and a file recording area 42, and the user data are sequentially recorded in this file recording area 42. On the other hand, in the index recording area 41, the index data, the number which is the same as that of files N of the recorded user data, and two null sectors EOFs following the index data are included.