Method for producing optical disk base

A method for producing an optical disk base having a center hole, which includes the steps of injecting a photo-curable resin into a cavity formed between a mold half having an information pattern and another mold half of flat plate which are placed opposite to each other, curing the photo-curable resin by irradiation with light, and demolding, wherein said photo-curable resin is injected into said cavity through an injection nozzle having an outside diameter which is substantially equal to the diameter of the center hole of the optical disk base, said injection nozzle having a forward end where the photo-curable resin exits the nozzle and having a horn-shaped opening at the forward end thereof;

• wherein the forward end of said nozzle is closed after injection;
• wherein said photo-curable resin is irradiated with light with said injection nozzle projected into said cavity so that said injection nozzle forms an unfilled well having a circular groove therein which facilitates the formation of the center hole;
• and wherein said center hole is punched out along said circular groove after said demolding.