PURPOSE: To obtain a sensor wherein solid electrolyte is effectively form in a thin film by forming a solid electrolyte thin film to cover an electrode on a silicon substrate and then making the silicon substrate porous by means of anode formation to form a diffusion limiting member.

CONSTITUTION: After a solid electrolyte thin film is deposited to cover an electrode formed on a silicon substrate, the silicon substrate is made porous by means of anode formation to have a diffusion limiting member formed while an electrode is formed also on the solid electrolyte thin film. By thus depositing the solid electrolyte on the silicon substrate before it is made porous, a dense solid electrolyte thin film can be formed while a porous body having uniform hole diameters with goods repeatability can be obtained by means of the anode formation, whereby a sensor with uniform characteristics can be obtained.