Manufacturing method for sensor element

A manufacturing method for a sensor element which detects the concentration of a specified gas contained in a measurement-object gas, comprising:

• a preparing step of preparing a plurality of green sheets made of ceramic, which is an oxygen-ion-conductive solid electrolyte, as a main constituent;
• a forming step including
• a step (a) of forming an unfired electrode made of a conductive paste on one of the plurality of green sheets,
• a step (b) of forming an unfired electrode lead and an unfired lead insulating layer on the same green sheet as in the step (a), the unfired electrode lead made of a conductive paste and to be connected to the unfired electrode, the unfired lead insulating layer made of an insulating paste and to surround at least part of the unfired electrode lead, and
• a step (c) of forming an unfired bonding layer made of a bonding paste so as to fill at least part of a region without the unfired lead insulating layer on the green sheet subjected to the step (b) and so as to overlap at least part of an edge portion of the unfired lead insulating layer;
• a stacking step of stacking the plurality of green sheets including the green sheet subjected to the steps (a) through (c) so as to form a multilayer body in which the unfired electrode lead is sandwiched between green sheets;
• a cutting step of cutting out an unfired sensor element from the multilayer body;
• and
• a firing step of firing the unfired sensor element to produce a sensor element including an electrode formed from the unfired electrode, an electrode lead formed from the unfired electrode lead, a lead insulating layer formed from the unfired lead insulating layer, and a bonding layer formed from the unfired bonding layer.