PURPOSE: To select plastics out of waste materials, such as paper and wood chips.

CONSTITUTION: While waste materials are dropped, in the drop path, a wind is horizontally fed by an air blower from crosswise to blow off paper or plastics of a small specific gravity into a horizontal path 3 disposed in the crosswise direction. By the wind force of the air blower, the waste materials of a small specific gravity horizontally come into collision with an upward travel part 4a of a hot plate 4. Paper and wood chips 15 in the colliding waste materials drop downward at once without attaching to the hot plate. With respect to plastics 16 colliding with the hot plate 4, the colliding part is melted by the heat of the hot plate to be fused to the hot plate 4. Thus, the plastics moves upward together with the hot plate 4. After moving upward, the plastics 16 successively moves downward. At this time, the plastics 16 is scraped off the hot plate 4 by an edge of a cutting knife 7 provided on the travel path.