<p>Disclosed is a controlled-potential electrolysis oxygen sensor which can acquire a stable output reliably even if an impact is applied thereto. The controlled-potential electrolysis oxygen sensor is constituted such that at least a working electrode and a counter electrode are disposed in a casing forming an electrolyte chamber, and such that a gas to be detected is limited in quantity by a panel cover member having a pin hole formed to extend therethrough and is fed to the working electrode. The controlled-potential electrolysis oxygen sensor is further constituted such that the working electrode formed to have an electrode catalyst layer on a gas-permeable base film is fixed on the inner face of the panel cover member through a liquid-impermeable film having a through hole, with which the pin hole of the panel cover member communicates and to which the outer face of the gas-permeable base film of the working electrode is exposed.</p>
