When wastes which are composites of metals, plastics, etc., such as refrigerators and washing machines, are fed into the screw crusher, the wastes are subjected to repeated impact and torsional action between the hammer, which is rotating at high speed, and the crush liner in a crushing chamber which gradually narrows. As a result of this process, the material being crushed, which is a composite material produced by methods including fitting, fastening, gluing, and coating, can be separated into loose parts based on differences in the strength, impact resistance, and ductility of the respective materials. Crushed fragments are then pelletized, increasing their specific gravity, and are discharged from a screen. As a result, it was possible to contribute to the recycling of wastes, the larger part of which had conventionally been disposed of by burial in landfills.