The invention relates to a sieve screen, which can be positioned in a utility machine-operated screen bucket or in a screening station maneuverable with its own actuator. A plurality of screening plates (3) are spaced from each other and establish a screening surface (2), which is provided with screening slots and on top of which can be placed the material to be screened. Rotatable shafts (4) are present below the screening surface (2). The shafts (4) feature blades (5), which protrude from the shafts and extend through the screening slots to above the screening surface (2). Fraction size is adapted to be changed without removing the shafts (4), by re-grouping the blades (5) and a necessary number of the screening plates (3). The blades (5) can be grouped in such a way on the shafts (4) that at least two blades (5) are set adjacent to each other and the adjacent blades are located within the same screening slot.