To improve the durability of a discharge body.

A discharge electrode 12 and an induction electrode 13 are arranged oppositely to each other no both sides of a ceramic base plate 11 being an dielectric base plate. The electrode 12 is covered with a protection layer 14. The electrode 12 is formed by firing paste of a mixture of a main component consisting of pyrochlore type oxide, an assistant component consisting of noble metal(s) and a binding material consisting of a glass-based dielectric substance. Any of Bi2Ru2O7, InBiRu2O7, Bi2Ir2O7 and GdBiRu2O7 is used as the pyrochlore type oxide and at least one of Pt, Au, Ag and Pd is used as the noble metal. The sheet resistance value per unit area of the electrode 12 is set to be 0.05-100 Ω/square by adjusting the content of the glass-based dielectric substance.