GAS SENSOR STRUCTURE

PROBLEM TO BE SOLVED: To provide a gas sensor structure which prevents short-circuit due to the condensation of an inner electrode of a sensor element and a heater.SOLUTION: A gas sensor structure comprises a cylindrical member sealed at the tip end; a sensor element having an inner electrode arranged on an inner surface of the cylindrical member and contacting with reference gas, and an outer electrode arranged on an outer surface of the cylindrical member and contacting with measured gas; a heater inserted in an internal space of the cylindrical member and heating the sensor element; an insulation member interposed between the inner surface of the cylindrical member and the heater, and insulating the inner electrode and the heater; an applying member for increasing a specific surface area applied on a surface of the inner electrode and/or the heater; a gas introducing hole penetrating the insulation member, and leading the reference gas to the inner electrode; and water sealing means provided at a connection part between an exterior electric wire and the inner electrode or the heater which are connected in the internal space of the cylindrical member.