Abstract: A device for measuring thermal conductivity of gas components of a gas mixture in order to determine fractions of the gas components includes a plurality of thermal conductivity sensors, each thermal conductivity sensor being a component of a resistance bridge circuit and being connected to an evaluation unit associated with the device. Each thermal conductivity sensor has a heating element and an integrated temperature measuring element, which elements generate two measuring voltages (UM3, UM2) when the temperature of the thermal conductivity sensor changes as a result of heat dissipation by the gas mixture. Voltages are compared in the evaluation unit in order to detect measuring errors.