GAS SENSOR

PURPOSE: To enhance the reliability of the gas sensor of a burner particularly to the level of detecting the deterioration of a catalyst layer of sensor characteristics of the maximum subject of a chemical sensor. CONSTITUTION: The gas sensor comprises heating means, further, a solid electrolyte layer 1, a pair of electrodes 2, 3 formed on both sides or the same side of the layer 1, a porous semiconductor metal oxide catalyst coating layer formed on the one side electrode and a third electrode 5 formed on the surface of the catalyst layer. The resistances of the catalyst layer and the electrolyte layer 1 are intermittently measured to detect the deterioration of the layer 4, and the catalyst life can be evaluated. Further, the function of controlling the burner by using an arithmetic circuit, a memory circuit, etc., via an interface by utilizing solid electrolyte output, and transmitting information of carbon monoxide concentration to a place spatially separated by using communication means are provided.