To provide a method and an apparatus for cleaning a resin product by removing a foreign matter such as a coating film, a plated film or a laminated label or the like on a surface so as to recycle the product as a raw material resin.

The method for cleaning the resin product comprises the steps of crushing the recovered thermoplastic resin product, supplying the product together with water to the cleaning apparatus in which at least a part of an inner surface of a container and/or a surface of a rotor is roughed by a rugged part or the like of a depth of 40 to 2,000 μm, after crushing to crushed pieces, rotating the rotor, and cleaning the pieces. The method further comprises the steps of continuously supplying the water from a plurality of positions of the apparatus, draining so that a water level in the apparatus becomes constant, and preferably cleaning the pieces while holding a mass ratio of the pieces to the water constantly. It is preferable to clean the pieces that the mass ratio of the pieces to the water in the apparatus is controlled to 1: (0.3 to 2.0) and that the water is drained while continuously supplying the water so that a temperature in the apparatus becomes 70°C or lower.