PURPOSE: To conveniently and inexpensively fractionate plastic particles by electrifying by friction different kinds plastic particles constituting a mixture in a different polarity, making the particles ball across an electric field to fractionate to a different zone without using a liq. such as water.

CONSTITUTION: The mixture 22 is composed of plastic particles 23 and the plastic particles 24 having a different triboelectric charge order, and the particles are electrified by rubbing each other or by rubbing with an inside wall of an agitator in an stirring stage. The mixture 22 reaches an outlet 5 and falls across a direct current electric field. The particles 23 charging in positive fall to a negative pole zone 18, and the particles 24 charging in negative fall to a ground pole zone 19. The mixture 22 charging unsufficiently or does not charging completely fall into an intermediate zone 20 Therefore, the mixture is conveniently fractionated without using an expensive device and the liq. such as water required to this.