Abstract: The connection conductor leading from the connection end of a sensor element towards the end of the sensor remote from the gas to be measured is a metallic connection part (17) that is rigid against torsion and passes through the aperture (16) of the closure shell (14) where it is sealed by a bead-like element (41) having a tubular extension (48), beyond which the connection conductor has an axial internal connection surface for a cable (19). A sleeve (51) of yielding material (51) covers the adjoining ends of the cable and of the connecting conductor and an overlay shell (52) compresses the sleeve to make a tight seal, both around the cable and against the tubular end of the bead (41). The overlay shell snaps on to the tubular extension of the bead by interlocking annular sawtooth ridges.