To precisely classify water-containing particle materials which easily granulate on the surface of a screen by containing water and by vibration, and to prevent clogging.

A vibrating screen is provided with a plurality of elastomer strips 32 arranged on the upper surface side of a particle adjusting screen 21 and impacting water-containing slug particles on the particle adjusting screen 21 and the upper surface of the particle adjusting screen 21 respectively by vibration, a plurality of exciting balls 23 arranged on the downstream side of the particle straitening screen 21 and impacting the lower surface of the particle adjusting screen 21 by vibration, and an exciting device 17 vibrating the particle straightening screen 21, the elastomer strips 32 and the exciting balls 23 respectively.