Filtration device having variable filter

PURPOSE: A filtration device of a multistage variable filter type is provided to improve filtration efficiency of a filter with a multistage variable filter, and to offer convenience in backwashing while reducing the entire washing time of the filter. CONSTITUTION: A filtration device of a multistage variable filter type comprises the following: a cylindrical housing(100) with a raw water inlet(110) and a processed water outlet(120); a plurality of filters(210,220) formed towards the housing, and arranged successively inside the device; an upper supporting plate(230) connected to a processed water discharge part; a backwashing water inlet(130) connected to the upper supporting plate on the top of the upper supporting plate; a compression plate(240) supporting the filter; a compression unit(300) releasing or adding the pressure; and a plurality of filter supporting plates(260).