To make clogging less and to enhance sieve efficiency by forming a dispersion device with both horizontal disks rotating around vertical shafts supported with bearings fixed in the lateral width direction of a vibration sieve and a rotational driving means, and providing a close circuit for returning a product on the sieve of the vibration sieve to a gyratory crusher.

The dispersion device 60 is a device for uniformly dispersing and feeding the product crushed by the gyrator in the lateral width direction, when the crushed product is conveyed with a belt conveyer and is fed to the vibration sieve 70, and is provided with a pair of left and right horizontal disks 64 arrayed around the vertical shafts with the bearings 65 by being away at the central part of a framework 61 horizontally laid over in the upper side width direction at the upstream side of the vibration sieve 70 and is rotated at an optional speed. Thus, raw materials charged into a shoot 62 of the dispersion device 60 are dropped on respective disks 64, scattered to the circumference, are distributed nearly uniformly in the width direction. The products on the sieve at the lowermost stage are classified at optional ratio and are conveyed to a returning line and a product line.