To precisely separate a mixture of particles of a conductive material and a plastic material which attract each other by being slightly electrified or wetted.

An electrification device 8 for monopolarly electrifying the mixture, a mixture supply apparatus 5 for supplying the electrified mixture, a slanted diaphragm 3 which is slanted at a prescribed angle, made of a conductive material, and electrified reversely to the polarity of the mixture electrified by the electrification device 8, and a vibrating device 4 for vibrating the diaphragm 3 to convey the mixture in the conveyance separation direction R different from the falling separation direction Q downward in the inclination direction are provided. The plastic particles in the mixture charged on the diaphragm 3 are attracted by image force, moved in the conveyance separation direction, and separated. The conductive material particles are electrified in the same polarity with the diaphragm 3 to repel the diaphragm 3 by the image force, moved in the falling separation direction, and separated.