An ultrasonic injection mold for an optical disk includes a movable die and a fixed die; a disk molding cavity formed between the movable die and the fixed die; a stamper positioned at the bottom of the cavity for forming a pit on a surface of the disk; and an ultrasonic generation device provided on the movable die or fixed die for applying ultrasonic waves to the cavity in performing infection molding. One or more slits are formed on the movable die and the fixed die in the direction which crosses the radial direction of the cavity. The ultrasonic injection mold minimizes the amplitude of the ultrasonic transmitted in the radial direction of the cavity.