A discharge electrode 5 for generating ions and a high-voltage generating circuit unit 2 that supplies the discharge electrode 5 with a high voltage are housed in a housing 3. A discharge opening 12 for discharging the generated ions is formed in the housing 3. The housing 3 is covered by an exterior case 15. The exterior case 15 is connected to the high-voltage generating circuit unit 2 and functions as an induction electrode. A passage opening 33 leading to the discharge opening 12 is formed in the exterior case 15. An insulating sheet 36 covers the periphery of the passage opening 33 in the exterior case 15 facing a space into which the ions are discharged so that the discharged ions do not attach to the exterior case 15. Decrease in the amount of discharged ions can be prevented while using a peripheral component of the discharge electrode 5 as the induction electrode.
