Oxygen sensor element and method for manufacturing same

A method for manufacturing an oxygen sensor element having a structure in which a predetermined portion on an outer surface of a ceramic sintered body as a sensing layer is covered with heat insulating layers, comprising the steps of:

• molding slurries, which are formed respectively by mixing raw materials for the ceramic sintered body together and by mixing raw materials for the heat insulating layers together, into a sheet form to manufacture a first sheet member and second sheet members;
• cutting each of the first sheet member and second sheet members into a predetermined size;
• layering the cut first sheet member and second sheet members so as to have respective predetermined thicknesses to form a layered body with the layered first sheet member sandwiched between the layered second sheet members in a vertical direction;
• cutting the layered body into a predetermined size and a predetermined shape to manufacture a sensor element;
• baking the sensor element;
• and
• forming a pair of electrodes on either end portion of the baked sensor element, wherein
• in the baking step, the first sheet member and second sheet members are baked simultaneously.