Patent ID: 8080143

Claim:
A method for manufacturing a gas sensor element comprising a solid electrolyte member, an electrode formed on the solid electrolyte member, and a protection layer including a reinforcement member having an insertion hole, and a porous electrode protection member provided in the insertion hole and adapted to protect the electrode from becoming poisoned, the method comprising: after disposing a green electrode protection member in the insertion hole of a green reinforcement member, pressing by a die that has a plane that presses both a surface of the green reinforcement member and a surface of the green electrode protection member such that the die presses both the green reinforcement member and the green electrode protection member so as to form a green protection layer; next arranging the green protection layer and a green solid electrolyte member in layers so as to form a laminate which will become the gas sensor element after being fired; and after the arranging step, firing the laminate, wherein before the pressing step is performed, the green electrode protection member has a thickness greater than that of the green reinforcement member, and wherein the reinforcement member and the electrode protection member have substantially the same thickness.