Abstract: A method of applying a synthetic resin layer to an outer surface of a metal part while the metal part is positioned within a powdered mass of a thermally fusible synthetic resin. The metal part within the powdered mass is induction-heated to a temperature between a melting point and a thermal decomposition point of the synthetic resin, to melt a portion of the powdered mass surrounding the outer surface of the heated metal part, and to deposit the molten portion of the powdered mass on the outer surface of the heated metal part, as the synthetic resin. The metal part is pushed down by a predetermined distance within the powdered mass, at least once at a point of time after the metal part has been positioned in the powdered mass, and before the induction-heating step has been completed.