PURPOSE: To provide a titled device simplified in processing stage and used for coal dressing, etc., by generating triboelectricity in powder to be selected, and sorting the powder in accordance with its charged quantities after introducing them to a sorting chamber having a DC electric field.

CONSTITUTION: Powder to be sorted such as finely-pulverized coal is fluidized by a gas and are introduced into an electrically charging device 5 to produce a swirling flow in the inside of a cylinder 52. By said flow, the friction caused between the powder and the inner surface of the cylinder 52 produces electric charges on the powder corresponding to the components of the powder, and then the powder is discharged from a discharging port 54. Next, the powder is introduced into a sorting chamber 9 in which a DC electric field is created by a pair of electrodes 901, 902, and are separated in accordance with the charged quantities of them into a high coal fraction, a coal and ash-mixed fraction, and an ash fraction, etc. In the chamber 9, because the electrodes 901, 902 are placed so that their recessed surface sides are faced each other, the intensity of electric field at the end of electrode is made larger to effectively prevent the powder from scattering out of the electrode system.