PROBLEM TO BE SOLVED: To surely sort an object having approximate specific weight by providing a belt conveyer inside a tunnel-shaped machine body having a sorting object slot while raising a plurality of crosspieces crossing a conveying direction at intervals on the surface of a belt in the lengthwise direction, and blowing air from the downstream side in the conveying direction to the upstream side in the machine body.
SOLUTION: An object mixed with a plastic product is put from a slot 35 along with the direction of an internal part C of a machine body 21. The flattened objects and heavy objects contained in the mixture are dropped and loaded on the conveying plane of an endless belt 53 of a belt conveyer 23. These objects are placed at a section sandwiched between a plurality of crosspieces 56 perpendicular to the conveying direction on the conveying plane of the endless belt 53 so that they are conveyed in a direction A together with the rotation of the endless belt 53 and dropped from a first discharge port 38 in a direction D. Then, a lightweight mixed film is conveyed towards the other terminal part of the machine body 21 on the wind. Besides, even when the mixture is put in, the films are carried in the air blowing direction B, dropped from a second discharge port 39 in the direction E and discharged.