To prevent a reduction in an amount of an ion emission while preventing generation of electromagnetic noise. A high-voltage generating circuit section (2) that supplies a high voltage to an ion generating element (1) that generates ions is housed in a housing (3), and sealed with filled resin (22). An emission port (12) for emitting the generated ions is formed in the housing (3), and an outer surface of the housing except the emission port is covered with a shield case (30). A passage port (33) communicating with the emission port is formed in the shield case. A periphery of the passage port of the shield case is covered with an electrically insulating covering sheet (36) so that emitted ions do not adhere to the shield case. The ions emitted from the emission port do not adhere to the shield case covered with the covering sheet.