A filter element for cleaning an operating liquid of a machine tool is provided with a pressure-stable jacket permitting flow therethrough. A filter medium is arranged in the pressure-stable jacket. A first end disc and a second end disc are seal-tightly connected to opposite ends of the filter medium. The filter medium surrounds an inner raw-side cavity. The pressure-stable jacket surrounds the filter medium and is connected fixedly to the first and second end discs. The first end disc has an inlet opening for the operating liquid. The second end disc has a drainage opening provided with a releasable closure element that closes the drainage opening.