Patent ID: 8127594

Claim:
A gas sensor comprising: a plate-shaped gas sensing element extending in a longitudinal direction and comprising a sensing portion provided at a leading-end side in the longitudinal direction, the gas sensing element comprising a plurality of stacked ceramic layers including a first ceramic layer having a first surface and a second ceramic layer having a second surface opposing the first surface, wherein the first ceramic layer has a first through hole, a first through hole conductor covering at least an inner surface of the first through hole, wherein the first ceramic layer comprises a first conductor formed on the first surface thereof, wherein the first conductor comprises: a first peripheral conductive portion provided at a periphery of the first through hole and electrically connected to the first through hole conductor; a first lead portion that is narrower than the first peripheral conductive portion; and a first contact conductive portion that is wider than the first lead portion, wherein the first peripheral conductive portion, the first lead portion and the first contact conductive portion are integrally formed and arranged in this order in the longitudinal direction, and wherein the second ceramic layer comprises a second conductor formed on the second surface thereof and electrically connected to at least the first contact conductive portion.