To carry out the precision filtration, make the clogging hard to generate and regenerate easily in the case of having generated the clogging actually by dividing a filter box of a tray-shaped structure by means of a plate-shaped filter medium made of a ceramic into upper and lower sections, forming a raw liquid feed camber in the upper chamber and also forming a vacuum suction chamber below the feed chamber.

The inside of a filter box 1 set rotatably with a supporting shaft 2 as its center is divided into upper and lower chambers by means of a flat plate-shaped ceramic film 3, and a raw liquid feed chamber 1a is formed in the upper section, while a vacuum chamber 1b is formed in the lower section. The vacuum suction chamber 1b is connected with a vacuum pump by a suction pipe 6 running through the inside of the supporting shaft 2. Also a raw liquid feed pipe 4 and a dehydrated cake cleaning pipe 5 are fitted above the feed chamber 1a, and an air blow pipe 7 is fitted above the supporting shaft 2. Cleaning water is jetted out of a cleaning pipe 10 in the state of rotating the filter box 1 by 10° and high pressure air is blown from the air blow pipe 7 at the time of cleaning and regenerating the ceramic film 3 to clean and regenerate the ceramic film surface.