Abstract: The present invention is for a conductivity metering device. The invention is primarily for conductivity meters which are used for level gauging of fouled liquids where the fouling materials may cause functioning problems of the metering probe. The probe is intended for metering of the conductivity between the probe body 1 and a tube 14, made from metallic material, in order to determine if there is liquid inside the tube. The probe body 1 is the outer tip of a piston 6 and it may be made as one piece with the piston or as a separate part which is mounted onto the piston. The piston 6 and parts connected thereto are movably mounted in the cover part 15 and the cap 8 by sealing slide bearings 4, 7. When metering does not take place the tube 14 is mostly filled with water at a certain overpressure relative to its surroundings. As the metering piston 6 is kept retracted by an active overpressure between the sealings 4 and 7 liquid is prevented from leaking in.