The present invention relates to a thermal conductivity detector, comprising a sensor block having two cavities for the purpose of accommodating gases, wherein one of the cavities is open and the other cavity is sealed and in each of the cavities there is disposed a thermistor and also sealing elements for the purpose of sealing the cavities, which sealing elements comprise electric current feed through elements, which are electrically connected to the respective thermistor disposed in the respective cavity. At least the sealing element in the sealed cavity is a glass to metal feed through element, which is welded to the sensor block to form a gas-tight joint. The present invention further relates to a method for the production of the thermal conductivity detector.