A nonconductor product is soaked in a solution suspending a semiconducting powder and is subjected to light irradiation in the solution so that polar group is formed on the surface of the nonconductor product, and then electroless plating is performed on the surface on which the polar group is formed. A resin product is subjected to electroless plating after ultraviolet treatment in which ultraviolet rays are irradiated through water or a solution is performed. Further, electroless plating or electroplating with a different or the same kind of metal is performed on the electroless-plated layer formed by electroless plating. With the method like this, the plated nonconductor product which does not cause problems such as environmental pollution and waste liquid treatment, and whose surface and plated coating is firmly adhered to each other, and, when a resin product is used as an object to be plated, deformation by heat of the resin product can be prevented, and moreover, the adherent strength of the plated coating can be improved.