Abstract: An apparatus for the ionization of gaseous oxygen, especially of oxygen in room air, for providing ionization air free of harmful substances and with a neutral charge. The device has a housing (1) preferably of an insulating material, with an inlet opening (6) and an outlet opening (7) for the oxygen or air and with an anode (10) and a cathode (11) disposed in the housing (1). Preferably the anode (10) and the cathode (11) are electrode wires extending crosswise to the direction of flow, preferably of copper with a coat of enamel. Ionization takes place free of harmful substances and electrostatic charges are eliminated as a result of providing two separate flow paths (12, 13) between the inlet opening (5) and the outlet opening (6), the anode (10) being disposed in one flow path (12) and the cathode (11) is disposed in the second flow path (13), and a backplate electrode (14), preferably common to both flow paths (12, 13) and placed at ground potential, being associated with both flow paths (12, 13).