A sieve device for fine-cleaning of grainy material after preliminary cleaning in an aspirator, having an inclined body made of separably integrated frames, in which replaceable stationary sieve are placed one below the other, the upper sieve having openings corresponding to the size of the grain, and the lower sieve having openings smaller than the grain, while a charging hopper is mounted in the upper, peripheral part of the body above the upper sieve. The each sieve consists of cascading identical flat sieve segments connected in sequence by z-shaped connectors, so that the planes of all sieve segments are parallel and above each z-shaped connector there is a set of plates mounted pendulously and independently on a bracket mounted on the frame of the body above the sieve, parallel to the z-shaped connector, the combined width of the plates in the set corresponding to the width of the sieve segment.