PURPOSE: To separate and store magnetic substance, nonmagnetic conductive substance and nonmagnetic nonconductive substance from mixed materials at the same time with one magnetic separator by using an alternate current electromagnet for the magnet of a magnetic separator and dropping the mixed materials into the alternating magnetic field.

CONSTITUTION: A magnetic separator main part 21 consists of drums 22, 23, a belt 24 and an electromagnet 25. The separating method is thus, first, an alternate current from a power source is flowed to the winding 27 of an alternate current electromagnet 25 and produces alternating magnetic field in the space before a magnetic pole face 21, and the changing period of the alternating magnetic field is so adjusted that the magnetic drawing force is larger than others among the forces which act on magnetic substance 13 while it passes through this magnetic field. Being dropped from the hopper 9 into the altenating magnetic field before the face 21, magnetic substance 13 is drawn to the face 21 and classified to the storing means 11, nonmagnetic conductive substance 14 is repulsed by the face 21 and classified to the storing means 29, and nonmagnetic nonconductive substance 15 falls not affected by the magnetic field and is classified to the storing means 30.