Abstract: The invention refers to a filter device for filtering sewage, wherein the filter device has a drum (16) pivoted around a rotation axis (1), wherein the filter device has numerous filter disks (2) running parallel to one another, attached to the drum (16) and that can be made to rotate together with it with the help of a driving device (3), whereby the filter disks (2) have, in each case, filter surfaces (4) running parallel to one another that delimit several hollow spaces (5) arranged in circumferential direction of the respective filter disk (2) and preferably in fluid connection to one another, in which case the hollow spaces (5) are in fluid connection with the drum (6) through one or several inlet openings (6), so that the liquid to be filtered can flow out to the exterior, starting from the interior of the drum (16) through the inlet openings (6) into the hollow spaces (5) and the filtrate can flow from there to the exterior via the filter surfaces (4).