Method for producing gas sensor element

A method for producing a gas sensor element extending in an axial direction and including a solid electrolyte body, a reference gas-side electrode and a measurement gas-side electrode disposed on surfaces of the solid electrolyte body, a measurement chamber to which the measurement gas-side electrode is exposed, a diffusive porous layer disposed in the measurement chamber and exposed to the outside, and a ceramic insulating layer forming sidewalls of the measurement chamber, the method comprising at least:

• a transferring step of preparing a sheet including a plurality of green diffusive porous layer pieces that are cut in advance to have prescribed dimensions and that later become, through firing, the diffusive porous layer and transferring the plurality of green diffusive porous layer pieces from the sheet onto an insulating first ceramic green sheet having a size that allows for production of a plurality of the gas sensor elements therefrom;
• an application step of applying an insulating paste that later becomes the ceramic insulating layer through firing to the first ceramic green sheet;
• a laminating step of preparing a second ceramic green sheet provided with a plurality of the solid electrolyte bodies each provided with the reference gas-side electrode and the measurement gas-side electrode and laminating the first ceramic green sheet onto the second ceramic green sheet to thereby form a ceramic laminate;
• a cutting step of cutting the ceramic laminate along prescribed cutting lines to obtain a plurality of gas sensor element pieces;
• and
• a firing step of firing the gas sensor element pieces to thereby obtain the gas sensor elements.