Gas sensor and gas concentration detection device

摘要

A gas sensor includes an element case 42 with an internal peripheral surface formed as a taper surface 100. A portion of a housing section 43 surrounded by the taper surface 100 and a protective film 48 is filled with a filler 49. When the filler 49 thermally expands at high temperature, the filler 49 is subjected to a component of force in an upward direction by the taper surface 100. Therefore, projection of an element portion 44 involving deformation of the protective film 48 is suppressed, a change DELTA L of a propagation distance L to a reflecting section 33 is also suppressed, and a detection accuracy never decreases. In addition, reverberation is reduced. <IMAGE>