GROOVE FORMING DEVICE AND POLISHING DEVICE FOR PITCH DISK AND GROOVE FORMING METHOD AND POLISHING METHOD FOR PITCH DISK USING SAME

PROBLEM TO BE SOLVED: To perform groove forming work to a pitch disk to be used for polishing optical crystals or optical glass without generating cutting dust or chip at all, or without generating fine flaws in a polished surface of the subject member, and achieve precise and high precision polishing work. SOLUTION: Plural groove forming rings 14 are detachably and position- movably inserted to a roughly pole-shaped groove forming rod member main body 2 of a groove forming device 1 to e fixed, the groove forming rod member main body 2 having the groove forming rings 14 is placed on an upper surface of a pitch disk 6 to cross around a rotation center of the pitch disk 6 to be capable of moving with play, and applied to stopper members 12A, 12B fixed on a polishing device main body part, the pitch plate is rotated, the groove forming rings 14 are applied to the upper surface of the pitch disk 6, and it is pressed and rotated to form grooves 6A concentrically, while a subject material A is applied to the upper surface of the pitch disk 6 to be polished by a polishing material holding device 8.