The invention relates to a polarization separating filter which can be integrated in a planar hollow conductor circuit and which is comprised of a central hollow conductor (1) in which two waves that are polarized in an orthogonally linear manner are capable of being propagated. One end of the central hollow conductor (1) is terminated by a short-circuit wall (2), and two hollow conductors (3, 4) are, in the vicinity of the short-circuit wall (2), coupled to two opposing walls of the central hollow conductor (1) in an at least approximately identical cross-sectional plane that extends perpendicular to the longitudinal axis of the hollow conductor. The hollow conductors (3, 4) coupled on the faces thereof to the central hollow conductor (1) are turned with regard to their cross-sections in such a manner that the fields therein are oriented orthogonally in relation to one another.