PURPOSE: To provide a method and compact apparatus for classifying powder finely and also enlarging the classifying region by combining other classifying factors in addition to electrostatic force.

CONSTITUTION: When a flat electric panel 1 is excited by six-phase voltage power source, a shifting electric field is produced around the linear electrode group 3 of the flat electric panel 1, and the separated electrode and the powder sample 19 on the surface of the film are charged with electricity, and they are shifted by generated electrostatic force. The sorting of this powder sample 19 is performed by inclining the flat electric panel 1 by the shaft 11 for adjustment of a tilt angle thereby adding gravity to the carriage force of the shifting electric field.