PURPOSE: To carry out separation correspondingly to physical properties based on dielectric constant of powder to be separated by applying voltage between electrodes facing each other and forming a path for feeding powder to be separated for the electric field provided with strong and weak gradients and providing a powder collecting box under the feeding path.

CONSTITUTION: Powder P to be separated is fed in the free state into a path 4 for feeding powder to be separated between electrodes 1a and 1b to change voltage is applied from a power source 2. Strong and weak gradients are formed in the electric field by the difference of interval between the electrode plates 1a and 1b. The material P fed into the feeding path 4 is dropped in a powder collecting box 3 through the locus P1 corresponding to dielectric polarization force based on the dielectric constant of the material and separated. That is, the powder P is drawn to the narrower part of the interval between the electrode plates 1a and 1b by the dielectric polarization force to be applied in the direction of stronger electric field, and passed through the locus P1 and collected in a device 3a of the powder collecting box 3. Likewise, the powder P with small dielectric constant follows the locus P2 in the wider interval of electrode plates 1a and 1b in a division 3b of the powder collecting box 3. Thus the powder P can be separated correspondingly to the physical properties by the dielectric constant of the powder itself.