Disclosed herein are an insulating base plated with a metal layer, a plating method thereof, and a transparent electrode including the insulating base. During the manufacture of a polymer layer, a structure of an interface layer between a surface of the polymer layer and a metal layer is modified, adhesion with metal is excellent and the polishability of the interface layer is reduced, and thus, the reflectivity of the metal layer is reduced and particular color impression of metal is reduced to obtain black-oxide treated properties. When the metal layer formed on the insulating base is used in a mesh-type transparent electrode having a fine pattern, sufficient adhesion with metal for forming a pattern is obtained and the reflectivity of an adhesion layer of the metal layer is reduced, thereby increasing the visibility. Accordingly, the insulating base may be suitable for products such as transparent electrodes or touch panels.