Gas sensor

摘要

A gas sensing element comprises a solid electrolytic element, a measured gas sensing electrode provided on an outer surface of the solid electrolytic element, and a reference gas sensing electrode facing a reference gas chamber. A heater is accommodated in the reference gas chamber. A contact portion is provided on an outer cylindrical surface of the heater so that the contact portion is brought into contact with an inside surface of the solid electrolytic element defining the reference gas chamber. A heating peak position of the heater is in the vicinity of the contact portion.