To efficiently and finely crush materials to be crushed and to sieve the crushed materials to required grain sizes.

This screen crusher consists of a revolving shaft 301, plural disks mounted at the revolving shaft 301 via desired spacings perpendicularly thereto and rotary blade members which are mounted the revolving shaft 301 in such a manner that these members project radially from their swiveling outer peripheral surface 302' between the adjacent disks. The rear surface side of a crushing screen formed to cover the rear surface side aperture of a bucket by the plural rotary crushers is provided with a back screen 4 facing the swiveling outer peripheral surfaces 305' of the rotary blade members. The materials to be crushed which are passed through the crushing screen are sieved through the back screen 4.