Abstract: A measuring arrangement for detecting the level of combustible gases mixed with air such as methane in air includes a measuring sensor responsive to the heat-conductivity of the proportion of the gas to be detected. The effect of the ambient temperature on the heat-conductivity measurement is eliminated through a simple circuit configuration consuming low power for a measurement of heat-conductivity alone as well as for such a measurement in combination with a reaction-heat measurement. For this purpose, the heat-conductivity sensor is connected to a constant-current source. A measuring takeoff circuit for the heat conductivity is connected in parallel to the heat-conductivity sensor and is provided in the form of a series circuit including a measuring signal terminal and a compensating voltage source.