PURPOSE: To reduce drastically eccentricity at the time of a disk drive, by a method wherein at the time of forming of a groove for tracking on a transparent disk having the center hole with a photo-setting resin, an inner circumference of the disk is positioned by being pressed with a jig having the same tapered angle as the clamp of the disk drive.

CONSTITUTION: Photo-setting resin PP is applied to a stamper 6 where a pin 7 has been set in the center of a guide groove, over which a transparent disk 1 is put slowly so that bubbles are not entered, and the transparent disk 1 is positioned by putting a centering jig 13 having the same tapered angle as a clamp tapered angle over the pin 7. Then a PP layer 2 is formed by applying ultraviolet rays to the surface of the transparent disk 1. Then the transparent disk/PP layer forming disk are removed from the stamper by removing the centering jig 13, and a guide groove forming process is completed. With this constitution, at the time of clamping to the disk drive, the same amount of deviation is generated in the opposite direction even if the deviation is generated once on the centers at the time of forming of the guide groove, therefore, the deviation on the centers is eliminated, and the center of the guide groove coincides with that of a clamp shaft.