Abstract: In an abrasion testing apparatus for determining abrasion in a screen caused by suction box coatings and the like in the cellulose and paper industry, a driving shaft (6) is provided on a drum (8), which drum is provided with suction device coatings at its circumference. The driving shaft is arranged vertically and the drum (8) is connected to the lowered end of the shaft and extends into the upper end of the tank (3) filled with filler suspension. The drum (8) is of hollow construction, has a plurality of openings (10) in its circumferential wall (8a) and is open at least at one end.