PURPOSE: To enable low-cost classification with simple installation by effecting the classification, as the sintered powder particles are electrically charged, when the powder of superconductive phase or a powder rich in the superconductive phase is separated from the sintered powder of oxide superconductor.

CONSTITUTION: A sintered powder P of an oxide superconductor such as YBaCuO superconductor is allowed to fall down from hopper 1, introduced into an electrostatic field between the cylindrical electrode 4 and the roller 3 of the rotary electrode whereby the powder P is electrically charged. The particles of superconductive phase or the powder particles containing a large amount of the superconductive phase A are electrically charged and repelled from the roller 3 to fall down in front of the roller 3. On the contrary, the particles scarcely containing or not containing the superconductive phase B are not electrically charged or less charged to stick to the surface of the roller 3 and removed from the roller with brush 5. Further, a part of the particles are repelled from the roller 3 to fall down just under or just before the roller 3. Thus, the powder A and the powder B can be separated.