A gas sensor control device (31 - 33) for controlling a gas sensor (21 to 23), the gas sensor comprising a pump cell, a sensor cell and a gas chamber, the pump cell configured to receive a pump cell supply voltage (Vp) so as to adjust a concentration of an oxygen gas component contained in a detection target gas introduced into the gas chamber on the basis of the received pump cell supply voltage (Vp), the sensor cell configured to detect a concentration of a specific gas component contained in the detection target gas after the concentration of the oxygen gas component contained in the detection target gas has been adjusted, the gas sensor control device (31 - 33) comprising a computer system comprising a central processing unit, the computer system comprises: a voltage switching part configured to adjust the pump cell supply voltage (Vp) to be supplied to the pump cell in the gas sensor; a pump cell output control part configured to adjust a variation range of a pump cell output current (Ip) of the pump cell, before and after the adjustment of the pump cell supply voltage (Vp) within a predetermined variation range; and a deteriorated state detection part configured to detect a deteriorated state of the sensor cell on the basis of an output variation of the sensor cell due to the adjustment of the pump cell supply voltage (Vp) performed by the voltage switching part characterized in that the pump cell output control part comprises a voltage setting part configured to determine the pump cell supply voltage (Vp) after the adjustment of the pump cell supply voltage (Vp) on the basis of the pump cell output current (Ip) of the pump cell before the adjustment of the pump cell supply voltage (Vp). the gas sensor comprising a pump cell, a sensor cell and a gas chamber, the pump cell configured to receive a pump cell supply voltage (Vp) so as to adjust a concentration of an oxygen gas component contained in a detection target gas introduced into the gas chamber on the basis of the received pump cell supply voltage (Vp), the sensor cell configured to detect a concentration of a specific gas component contained in the detection target gas after the concentration of the oxygen gas component contained in the detection target gas has been adjusted, the gas sensor control device (31 - 33) comprising a computer system comprising a central processing unit, the computer system comprises: a voltage switching part configured to adjust the pump cell supply voltage (Vp) to be supplied to the pump cell in the gas sensor; a pump cell output control part configured to adjust a variation range of a pump cell output current (Ip) of the pump cell, before and after the adjustment of the pump cell supply voltage (Vp) within a predetermined variation range; and a deteriorated state detection part configured to detect a deteriorated state of the sensor cell on the basis of an output variation of the sensor cell due to the adjustment of the pump cell supply voltage (Vp) performed by the voltage switching part characterized in that the pump cell output control part comprises a voltage setting part configured to determine the pump cell supply voltage (Vp) after the adjustment of the pump cell supply voltage (Vp) on the basis of the pump cell output current (Ip) of the pump cell before the adjustment of the pump cell supply voltage (Vp). a voltage switching part configured to adjust the pump cell supply voltage (Vp) to be supplied to the pump cell in the gas sensor; a pump cell output control part configured to adjust a variation range of a pump cell output current (Ip) of the pump cell, before and after the adjustment of the pump cell supply voltage (Vp) within a predetermined variation range; and a deteriorated state detection part configured to detect a deteriorated state of the sensor cell on the basis of an output variation of the sensor cell due to the adjustment of the pump cell supply voltage (Vp) performed by the voltage switching part characterized in that the pump cell output control part comprises a voltage setting part configured to determine the pump cell supply voltage (Vp) after the adjustment of the pump cell supply voltage (Vp) on the basis of the pump cell output current (Ip) of the pump cell before the adjustment of the pump cell supply voltage (Vp).