PROBLEM TO BE SOLVED: To provide a discharge ionization current detector which can be manufactured at low cost and is excellent in durability. SOLUTION: An electrode structure 19 consisting of a dielectric-coated metal tube 16 and an insulator-coated metal wire 18 inserted into the dielectric-coated metal tube is inserted from an upper side into an inside of a first gas passage including a dielectric tube 10. The metal tube 16 is connected to the ground on the upstream side of the first gas passage. One end of the metal wire 18 is extracted from the upstream side to the outside of the first gas passage and connected to a bias power source 33. An area not covered with the insulator is provided at the other end of the wire and the area is disposed in a second gas passage connected to the downstream side of the first pas passage. Further, a metal electrode consisting of a flanged metal tube 28 is disposed in the second gas passage and connected to an ionization current detecting circuit 34, thereby enabling reducing a contact part, between the metal and an insulating member, from the second gas passage which becomes high in temperature, improving durability and reducing the amount of use of expensive high-heat-resistant sealants and insulating members. COPYRIGHT: (C)2013,JPO&INPIT
