Disclosed is a filter device, especially for filtering liquids in internal combustion engines, comprising a filter element (4) that is to be penetrated in a radial direction and is disposed in a filter housing (2). A check valve (10) which is embodied as a nozzle valve and is provided with flexible wall sections is inserted into the filter housing. The internal faces of said flexible wall sections define a flow outlet while the external faces thereof are in contact with the liquid in the filter device.