To provide an ionizer capable of eliminating problems which a DC type ionizer and an AC type ionizer respectively face.

The ionizer generates ions by corona discharge by applying high voltages on a plurality of discharge electrodes. A plurality of discharge electrodes are divided into, for example, two groups of discharge electrodes 141, 142, and AC voltages of the same phases are applied in a lump on the discharge electrodes belonging to an individual group, and AC voltages of different phases (for example, inverse phase) at each group are applied to the two groups of discharge electrodes 141, 142 by controllers 41, 42. Otherwise, the ionizer is provided with a single controller 41 for applying AC voltages on the discharge electrodes and a delayed circuit 51 to delay by a prescribed phase the AC voltage outputted by the controller 41, and AC voltages of the same phases are applied in a lump to the discharge electrodes 141 by the controller 41 and the AC voltages outputted by the delayed circuit 51 are applied in a lump to the discharge electrodes 142.

COPYRIGHT: (C)2008,JPO&INPIT