The present invention is directed to provide a geothermal air-conditioner device utilising the earth's temperature and electrical field for processing—preheating, cooling and purifying—room intake air. This air-conditioner device includes at least one first pressure reducing chamber (1) with air intake opening (8) and second pressure reducing chamber (2) with processed air outlet (9), whereas these chambers are connected to each other by air conduits (3) located in the ground for conveying air from the first pressure reducing chamber (1) to the second pressure reducing chamber (2). The earth layer (4) on the air channels (3) is covered by a coarse material layer (5), under which at least one first ventilation conduit (6) is extending, through which coarse material layer is connected to air in chamber (1). Likewise there is exhaust ventilation piping (7) to provide exhaust from the coarse material layer (5) located.