There are disclosed a surface hardening method for resins and a surface hardened resin, capable of reforming the surface of a plastics disk substrate at low energy in a short time, and a production device of such a resin. The formation of an ion-implanted layer (11) by implanting equal to or more than 10 17 carbon ions per cm 2 into the surface of a plastic disk substrate (10) at equal to or less than 20 KeV and the formation of a thin film (12) of high hardness on the ion-implanted layer (11) are performed alternately or simultaneously, and the hardening rate is increased further by using a bias device.