A filtering device includes multiple filtering elements (3) with bodies defining longitudinal axes. The filtering elements (3) are arranged adjacent to one another in a housing such that the longitudinal axes extend parallel to one another. The bodies of at least some of the filtering elements (3) have a shape that deviates from a circular cylinder at at least one part of the body length. The filtering elements (3) with bodies having a shape deviating from a circular cylinder have a cross-sectional size at least partially changing from one end to the other end. The filtering elements are oriented in the housing such that the regions of a larger cross-section are associated with the regions of a smaller cross-section in adjacent filtering elements.