Patent ID: 7266459

Claim:
A gas detecting device using a gas sensor element changing an electrical characteristic depending on a concentration of a specific gas, comprising: acquiring means for acquiring a sensor output value by using the gas sensor element; first deciding means for deciding whether or not a first deciding object value calculated by using the sensor output value satisfies a first relationship for a first threshold; second deciding means for deciding whether or not a second deciding object value calculated by using the sensor output value through a different calculating method from the method of calculating the first deciding object value satisfies a second relationship for a second threshold; concentration signal generating means for generating either a low concentration signal or a high concentration signal; and concentration signal generating means for generating the high concentration signal in place of the low concentration signal when the first relationship is satisfied by the first deciding means for a period in which the low concentration signal is generated, and for generating the low concentration signal in place of the high concentration signal when the second relationship is satisfied by the second deciding means for a period in which the high concentration signal is generated.