A plate filter element for a filter device may include a filter body having a peripheral edge, which has at least two rectilinear wall sections, which border each other and forming a corner. A seal may be attached to the filter body and be arranged peripherally along the edge. The seal may have an inner contour running around the inside and an outer contour running around the outside. The inner contour may run parallel to the rectilinear edge sections into the respective corner. The outer contour may run parallel to the rectilinear edge sections to a corner region, which contains the respective corner and end sections of the rectilinear edge sections border the respective corner regions. The outer contour may form a bulge, which curves outwards in relation to rectilinear sections of the outer contour, in the corner region.