Abstract: The invention relates to a sealing and insulating construction of a sensor for pressurized working conditions. The construction comprises a pressure balancing chamber (1) which is open towards the pressurized space, a sensor (4) which is partly located within the chamber and partly protrudes therefrom, as well as a conductor (6) insulated from the housing (2) and coupled to the sensor (4), and brought into the chamber via a leadthrough (5). Moreover, the construction includes insulation (7) for filling the space that surrounds the chamber around the sensor, as well as a piston (8) for separating the insulation around the sensor from the pressurized space, so that under pressure the sensor is evenly loaded on all sides, and consequently not subject to such tensions that could break it.