The present invention relates to suppress the optimum can not become that maintain the distance due to the discharge part and the counter electrode to changes in ambient temperature. A discharge electrode (70) is made of a metal material, a plate-shaped electrode support plate (71), are arranged along the side edges of the electrode support plate (71), the counter electrode (60) a plurality of discharge portions supported by the side edge portions of such opposite electrode support plate (71) and (73, 74). Insulating member (41) is, in the electrode support plate (71), to support the intermediate region (71a) between the discharge portion to be disposed at both ends of the plurality of discharge portions (73,74) (73a, 74a) support section with a (47).FIELD 12【課題】周囲温度の変化に起因して放電部と対向電極の距離を最適に維持できなくなることを抑制する。【解決手段】放電電極(70)は、金属材料で構成され、板状の電極支持板(71)と、電極支持板(71)の側縁部に沿って配列され、対向電極(60)に対向するように電極支持板(71)の側縁部に支持される複数の放電部(73,74)とを有する。絶縁部材(41)は、電極支持板(71)における、複数の放電部(73,74)のうち両端に配置される放電部(73a,74a)の間の中間領域(71a)を支持する支持部(47)を有する。【選択図】図12
