To provide the subject apparatus sufficiently charging specific plastic pieces within a short time by repeatedly using a friction auxiliary material and capable of discharging charged plastic pieces without hindrance.

A freely rotatable inner cylinder 32 is provided in an outer cylinder 31 equipped with a charging port 37 and a discharge port 39, and the inner cylinder 32 is formed into a reticulated form having a large number of meshes piercing through the reticulated form. Particles of either one of plastics are housed in the inner cylinder 32 as a friction auxiliary material 52 so that a ratio of specific plastic pieces 1 to plastic pieces 1 having polarity inverse to that of the specific plastic pieces 1 becomes equal in a charge row of plastic pieces of a plurality of kinds and the particles of the friction auxiliary material 52 are formed so as to be made larger than the plastic pieces 1 and the meshes of the inner cylinder 32 are made larger than the plastic pieces 1 but smaller than the particles of the friction auxiliary material 52.