The present invention relates to a device for cleaning of indoor air comprising capacitor precipitators (12a, 12b) each consisting of two electrode elements or two groups of electrode elements connected to the respective pole of a high voltage source, air transported fans (13a, 13b), at least one corona electrode (K1, K2) and at least one counter electrode (16a, 16b, 16c), wherein said corona electrode (K1, K2) and said counter electrode (16a, 16b, 16c) are connected each to a pole of a high voltage source. The characteristics of the apparatus of the present invention is that it comprises two air flow ducts (L1, L2) for the air to be cleaned, which air flow ducts (L1, L2) are placed along an axial reference line (AA) at a distance (d) from each other in the direction of the axial reference line (AA), that each air flow duct (L1, L2) is associated with a capacitor precipitator (12a, 12b) and an air moving fan (13a, 13b), that at least one corona electrode (K1, K2) is provided in the space between the air flow ducts (L1, L2), that at least one counter electrode (16a, 16b; 16) is located adjacent to the air flow ducts (L1, L2) circumference, that the air flow direction through the one air flow duct (L1) is diametrically opposite the air flow direction through the second air flow duct (L2) and that the air to be cleaned is passed into the space between the air flow ducts (L1, L2).