To provide a filtering device of a simple structure, requiring a short time for treatment, and effectively breaking and dropping filter cake from filter cloth.

The filtering device 100 includes: a fixed filter plate 10; a movable filter plate 20 movable while facing the fixed filter plate; the filter cloth 30 having an opening at least at a lower part; and a filter frame 40 forming a sealed filtering space by sandwiching filter cloth faces to close the opening of the filter cloth. Raw liquid to be filtered is pressurized at a predetermined pressure and supplied into the filtering space by a raw liquid injection device 50, then a dewatering/filtering process is performed by moving the movable filter plate 20 by a filtering control part 60 toward the fixed filter plate 10 at a predetermined pressure, and the movable filter plate 20 is separated from the fixed filter plate 10, and the filter cloth 30 is removed from the filter frame and suspended. By applying impact from the side edge directions of the filter cake plate-likely pressed in the filter cloth 30 by a filter cake dropping promoting device 70 to break the filter cake in the filter cloth 30 to promote dropping.