A hub-mounted optical disk to eliminate the need for a separate stack ring while decreasing the overall height, a method of fabricating the optical disk, and an injection molding die for manufacturing an optical disk substrate. The hub-mounted optical disk includes a substrate having a hollow and an indented portion engraved to a predetermined depth on the inside of a non-recording surface where no information is recorded; and a hub including a plate that has a fitting hole therein and is engaged into the hollow and the indented portion and a central ring that is inserted into the fitting hole. The method of fabricating the hub-mounted optical disk includes mounting the hub onto a magnetic chuck, applying an ultra-violet (UV) hardening resin on the indented portion of the substrate, operating the magnetic chuck so that the plate is in contact with the indented portion, and curing the UV hardening resin by irradiating it with UV light. The injection molding die for manufacturing the optical disk substrate includes a stationary plate having an injection nozzle that allows resin forming the substrate to be injected, a stamper that has a predetermined information recording pattern, and a moving plate having a projecting portion at the center.