Controlled potential electrolysis gas sensor

A controlled potential electrolysis gas sensor including at least a working electrode and a counter electrode which are provided in contact with an electrolytic solution to detect a concentration of a detection target gas in a gas to be tested by detecting a current flowing between the working electrode and the counter electrode in a state in which the working electrode is controlled at a constant set potential,

• the controlled potential electrolysis gas sensor comprising an operation control circuit configured to drive the controlled potential electrolysis gas sensor for a predetermined amount of time from an activation of an operating power source, under energization conditions capable of obtaining a state in which a current in a reverse direction, exhibiting an output characteristic compensating a sensor output initial fluctuation characteristic based on a current in a forward direction detected when the controlled potential electrolysis gas sensor is activated under energization conditions at a time of a gas detection operation, flows between the working electrode and the counter electrode,
• wherein the operation control circuit includes a potentiostat configured to control the working electrode so as to have the constant set potential,
• the potentiostat includes an operational amplifier having an output terminal connected to the counter electrode,
• the operational amplifier includes a non-inverting input terminal and a positive power source terminal, the non-inverting input terminal is connected to a reference voltage power source, and the positive power source terminal is connected to the operating power source,
• the operation control circuit further includes a short circuit that short-circuits the counter electrode to the operating power source,
• the operation control circuit is configured to apply a power source voltage of the operating power source to the counter electrode by the short circuit to obtain a state in which the current in the reverse direction flows between the working electrode and the counter electrode.