OPTICAL DISK

PROBLEM TO BE SOLVED: To provide an optical disk, wherein identification information such as ID number can be prevented from being accessed by a third person and there is not a fear that the identification information is lost, independently of a mode of distribution of a disk. SOLUTION: An optical disk (100) in which an identification information (16) is given and the identification information (16) is hidden by a scratch layer (14) is provided. Since this optical disk can hide identification information even by simple packing, leakage of identification information, double utilization, or the like can be prevented, while it is suitable for distribution of novelties or the like as a marketing tool. COPYRIGHT: (C)2006,JPO&NCIPI