In an air filtering apparatus in which power is supplied from a power supply to electrodes in an electrolytic bath to electrolyze water in the electrolytic bath and thus generate electrolytic water and the generated electrolytic water and air are supplied to a gas-liquid contact member to filter the air, a voltage varying unit varies the voltage applied between the electrodes, and includes a voltage switching unit for switching a power supply voltage, a voltage adjusting unit for adjusting the power supply voltage switched by the voltage switching unit and applying the adjusted voltage between the electrodes and a controller for controlling the voltage switching unit so that the power supply voltage is adjusted to a voltage nearest to the adjusted power supply voltage by the voltage adjusting unit.
