Abstract: The invention concerns a sensor construction for, e.g., the measurement of gas concentration, including a sensor element; a heating element arranged in conjunction with the sensor, with which the sensor element can be brought to a temperature above the ambient gas atmosphere temperature; and an electronics circuitry section, with which the desired electrical properties of the sensor element can be measured and the heating element of the sensor can be controlled. According to the invention, the sensor element and the electronics circuitry are placed onto the same planar substrate, and the substrate is processed to have adjacent openings around the sensor element area to the immediate vicinity of the area so that the openings extend through the substrate whereby the sensor area is connected to the surrounding part of the substrate and, then, to the electronics circuitry section, only along thin isthmuses remaining between the openings.