Patent ID: 8377273

Claim:
A gas sensor comprising: a substantially cylindrical metal shell; a laminated sensor element held within the metal shell, the sensor element including: a plate-shaped solid electrolyte layer extending in a longitudinal direction; an electrode portion laminated on the solid electrolyte layer; and a lead portion connected with the electrode portion and extending in the longitudinal direction, wherein the sensor element includes an insulating layer laminated on the solid electrolyte layer; and the lead portion has a front end portion laminated on the solid electrolyte layer, and a rear end portion laminated through the insulating layer on the solid electrolyte layer, wherein the insulating layer has an end portion over and across which the lead portion extends, and the end portion of the insulation layer has a recessed shape or a raised shape in the longitudinal direction as viewed in the lamination direction, and wherein the recessed shape of the end portion of the insulation layer is an entirely concave shape or the raised shape of the end portion of insulation layer is an entirely convex shape.