PURPOSE: To obtain an apparatus for performing the classification of ultrafine particles, by forming meshes, to which an AC power source capable changing frequency and voltage to be applied is connected, between linear electrodes applied to the front and back surfaces of a dielectric board by print wiring.

CONSTITUTION: Ultrafine linear electrodes 2a, 2b are applied to the front and back surfaces 1a, 1b of a dielectric board 1 formed of a silicon wafer by print wiring to form rectangular meshes 4 and the electrodes are connected to an AC power source capable of changing frequency and voltage to be applied. Further, communication holes 8 are bored in the central parts of the meshes 4 by laser beam. Because lines of alternating electric force are generated between ultrafine linear electrodes 2a, 2b, when particles 1 are supplied to the board 1, charge quantity also changes by the size or dielectric constant of the particles and large particles float by the obstruction force of the lines of electric force and small particles fall under gravity. Therefore, the falling particles can be classified through the communication holes 8.