Abstract: The invention relates to an apparatus for separating contaminants comprising a tubular filter body (12) having an inner flow space (18) which is separated by a filter layer (14) from an outer flow space (20). The one end face of the filter body (12) is closed and the other end face comprises an opening. The inner flow space (18) has a substantially uniform cross-section over its entire axial length and is in flow communication on the one hand through the filter layer (14) with the outer flow space (20) and on the other hand through the end-face opening with an outside space. In the inner flow space (18) an element (30) is arranged for conducting the flow through the filter layer (14), which is characterized in that said element (30) for conducting the flow from or to the filter layer (14) is gradually tapered in its cross-section from the sealed end face (16) to the end-side opening (22) of the inner flow space (18).