Abstract: The materials to be treated, for instance, molded resin articles with resin films coated thereon are treated by relatively simple means to separate and remove the resin film coatings from the surfaces thereof, and are further treated to recover them as a raw-form of resin material or a resin material regulated such that its particle diameter lies within a given particle diameter range, or the materials to be treated, for instance, powder materials are pulverized and granulated. A molded resin article is crushed to small pieces, to which compression impacts based on fine vibrations are in turn applied for squeezing, and resin film coatings separated off the small pieces are removed. The thus treated small pieces are further re-pulverized, and frictional crushing impacts are applied to the thus pulverized pieces as well for polishing and size-regulation.