Abstract: The invention relates to a purifying device for liquid, that has filtering means (1) in order to separate impurities in the liquid to be treated by mechanical filtration and purifying means (2), such as an activated carbon element or like, in order to eliminate impurities in the liquid to be treated by absorption or correspondingly, which means (1, 2) are arranged essentially built-in therein. The mechanical filtering means (1) are carried out by a thin filtering film (1a) made of plastic based material, such as PTM (Particle Track Membrane), TeM (Track-edge Membrane) or like, the porosity of which is 5-15%, the thickness preferably 10-25 &mgr;m and the size of pores 0,5 &mgr;m at its height.