The method of detecting the hydrogen concentration by using a first heat-generating resistor of which a first electrophysical quantity varies depending upon the hydrogen concentration and a second heat-generating resistor which is neighboring said first heat-generating resistor in a direction of gas flow and of which a second electrophysical quantity varies depending upon the hydrogen concentration as does the first electrophysical quantity, to detect the concentration of hydrogen based on the first electrophysical quantity and the second electrophysical quantity, the method comprising: calculating the amount of change in a target physical quantity, which is either the first electrophysical quantity or the second electrophysical quantity, calculating the correction amount based on a difference between the first electrophysical quantity and the second electrophysical quantity, and a calculating the concentration of hydrogen based on a difference between the amount of change in the target physical quantity and the correction amount.