GAS DETECTING METHOD AND ITS DEVICE

PROBLEM TO BE SOLVED: To improve detection accuracy by compensating for the lowering of the concentration dependency of a gas sensor in a high concentration region. SOLUTION: In the method for detecting gases such as a carbon monoxide as periodically changing the temperature of a metal oxide semiconductor of which the resistance value changes due to gas, the timing for measuring the resistance value of the metal oxide semiconductor is provided with at least two types of first timing and second timing. The gas is detected mainly at the resistance value at the first timing. In the case that the obtained detected value of the gas satisfies predetermined conditions, the gas is detected mainly at the resistance value at the second timing.