The present invention relates to a filter device for removing impurities contained in liquid. A filter housing 18 is provided with a container for accommodating a filter bag 2 therein, a deposit recovery tank 3 for recovering a deposit and a floating material recovery tank 4 for recovering a floating material. Thus, it is possible to prevent any deterioration of filtration performance caused by filtered and separated impurities, and to achieve both of filtration and specific gravity difference separation by a single device.