To provide a classifying apparatus which separates and classifies particulates from fine powder in raw material slurry accurately.

A cuplike rotor 4 installed at the end of the shaft of a first rotation shaft 3 and a core rotor 7 that is installed at the end of the shaft of a second rotation shaft 5 rotating around the same direction with the velocity difference from the first rotation shaft 3 and that is mounted within the rotor 4 so that it is rotatable are arranged in a casing 2. The core rotor 7 consists of an arm and agitation blade 7a of the arm edge wherein the agitation blade 7a includes a concave groove 19. The raw material slurry and diluted water are supplied into the rotor 4 through the concave groove 19 from the shaft aperture 16 of the second rotation shaft 5. While the raw material slurry supplied into the rotor 4 is agitated together with the diluted water, the course particles among the fine powder sediment on the inner peripheral surface countering to the stream towards the rotation shaft among the streams discharged towards the outlet with the action of the centrifugal force by the rotation of the rotors 4, 7. Meanwhile, the particulates are discharged on the stream. The course particles precipitated on the inner peripheral surface within the rotor are sucked and discharged from the shaft aperture 9 of the first rotation shaft 3.