Gas sensor having enhanced external connectivity characteristics

Abstract

A small-sized highly accurate gas sensor, which is excellent in its reliability of electric connections between contacts and fixtures while being freed from any damage, includes a base member; a detecting unit mounted on the base member for detecting a gas concentration; electrodes mounted on the detecting unit; cylindrical contacts buried integrally in an end portion of the base member; and electric leads interposed between the cylindrical contacts and the electrodes. Contacting fixtures for external lead wires are fitted in and contact the cylindrical contacts so that they are connected to the cylindrical contacts. The cylindrical contacts are formed in their openings with engaging entrances having a smaller diameter than the internal diameter, and the contacting fixtures include elastic contacting portions adapted to be diametrically reduced, when inserted into the cylindrical contacts, than the engaging entrances and expanded, after inserted, to become larger than the engaging entrances and to contact the inner walls of the cylindrical contacts.