Gas sensor

A gas sensor comprising:

• a laminated body which has a plurality of laminated oxygen ion conductive solid electrolyte layers and is inwardly provided with a measurement-object gas flow section, the measurement-object gas flow section being a section into and through which a measurement-object gas is introduced and flows;
• a reference electrode which is disposed inside the laminated body, and a reference-gas introduction section open outward of the laminated body and introducing a reference gas, the reference gas serving as a reference for detection of a specific gas concentration in the measurement-object gas;
• a measurement electrode provided on an inner circumferential surface of a measurement chamber of the measurement-object gas flow section;
• a measurement-object gas side electrode disposed on the laminated body such that the measurement-object-gas side electrode comes into contact with the measurement-object gas;
• a control device that performs oxygen pumping control to pump oxygen from surroundings of the measurement-object gas side electrode into surroundings of the reference electrode;
• and
• a calculation device that, during execution of the oxygen pumping control, measures a pump current for concentration detection when oxygen originating from the specific gas is pumped out from surroundings of the measurement electrode so that a voltage across the reference electrode and the measurement electrode reaches a target voltage, and calculates the concentration of the specific gas in the measurement-object gas based on the pump current for concentration detection,
• wherein the calculation device is configured to correct the concentration of the specific gas in the measurement-object gas based on a difference between a first base voltage and a second base voltage, the first base voltage being the voltage across the reference electrode and the measurement-object gas side electrode when the oxygen pumping control is not performed, the second base voltage being the voltage across the reference electrode and the measurement-object gas side electrode when the oxygen pumping control is performed.