Gas sensor

Abstract

A gas sensor 100 comprises a sensor element 101 and a control device 95. The sensor element 101 comprises an element body 102, a main pump cell 21, a first measurement pump cell 50, a second measurement pump cell 41, and a reference electrode 42. The second measurement pump cell 41 includes a second measuring electrode 44 (third inner electrode). The control device 95 performs second measuring electrode degradation determination processing for determining degradation of the second measuring electrode 44 on the basis of a voltage V2 between the second measuring electrode 44 and the reference electrode 42 while main pump control processing and first measurement pump control processing are being executed and second measurement pump control processing is stopped, and a pump current Ip2 flowing to the second measurement pump cell 41 while the main pump control processing, the first measurement pump control processing and the second measurement pump control processing are being executed.