PURPOSE: To prevent forming of such an optical disk that tracking control is made unstable by stopping recording to an original disk when correlation between bit patterns of adjacent two information tracks becomes a prescribed value or more.
CONSTITUTION: A pit pattern of a track T1 already recorded is divided into four regions of a rotary angle θ4-θ1, θ1-θ2, θ2-θ3, and θ3-θ4 of the original disk through a position detecting means 4, and stored in a first storage means 1 of an adjacent pattern testing device 20. A pit pattern is stored in a second storage means 2 in the same way at the time of recording in an adjacent track T2 of the outside of the track T1, correlation between storage pit patterns in the same rotary regions is detected by a correlation detecting means 3, when correlation value exceeds a prescribed value, recording in the original disk is stopped by an alarm signal from the means 3. Thereby, it is prevented that a disk in which the same pit pattern is continued over a long region and tracking control at the time of reproducing becomes unstable, is formed from the original disk.
KUROIWA TOSHIO
MATSUI KAZUNARI
