Abstract: Injection molding halves for forming disks having a plurality of cavities between a stationary mold unit, in which a plurality of sprue bushings and a runner with gates for introducing molten resin into said plurality of cavities are provided, and a movable mold unit in which a plurality of punches are provided concentrically to the sprue bushings for severing a central aperture of the molded disk, and an interval mechanism for providing a predetermined interval between a stationary mold unit and stationary mold base plate to ease the removal of escaped material, and connecting structure for connecting the stationary mold unit and the stationary mold base plate by alternative rotating of a connecting rod.