A hydrogen concentration measuring device comprising: a sensing film; an electric resistance detector (2, 12) which is configured to detect an electric resistance of the sensing film; and a transmitted light intensity detector (3, 11) which is configured to detect a transmitted light intensity of the sensing film; characterized in that the sensing film includes a metal oxide film and is configured to be placed in a gas atmosphere; and the hydrogen concentration measuring device further comprises: a controller (13, 14a) which is configured to perform: first hydrogen concentration measurement processing whereby to measure a first hydrogen concentration in the gas atmosphere on the basis of the electric resistance detected by the electric resistance detector, second hydrogen concentration measurement processing whereby to measure a second hydrogen concentration in the gas atmosphere on the basis of the transmitted light intensity detected by the transmitted light intensity detector, and, if the first hydrogen concentration is in a first measurement range and the second hydrogen concentration is in a second measurement range, wherein the second measurement range has at least a part overlapping with the first measurement range, measurement value correction processing in which a weighted average value of the first hydrogen concentration and the second hydrogen concentration is calculated thereby to determine a measurement value of the hydrogen concentration in a range in which the first measurement range and the second measurement range overlap. a sensing film; an electric resistance detector (2, 12) which is configured to detect an electric resistance of the sensing film; and a transmitted light intensity detector (3, 11) which is configured to detect a transmitted light intensity of the sensing film; characterized in that the sensing film includes a metal oxide film and is configured to be placed in a gas atmosphere; and the hydrogen concentration measuring device further comprises: a controller (13, 14a) which is configured to perform: first hydrogen concentration measurement processing whereby to measure a first hydrogen concentration in the gas atmosphere on the basis of the electric resistance detected by the electric resistance detector, second hydrogen concentration measurement processing whereby to measure a second hydrogen concentration in the gas atmosphere on the basis of the transmitted light intensity detected by the transmitted light intensity detector, and, if the first hydrogen concentration is in a first measurement range and the second hydrogen concentration is in a second measurement range, wherein the second measurement range has at least a part overlapping with the first measurement range, measurement value correction processing in which a weighted average value of the first hydrogen concentration and the second hydrogen concentration is calculated thereby to determine a measurement value of the hydrogen concentration in a range in which the first measurement range and the second measurement range overlap. first hydrogen concentration measurement processing whereby to measure a first hydrogen concentration in the gas atmosphere on the basis of the electric resistance detected by the electric resistance detector, second hydrogen concentration measurement processing whereby to measure a second hydrogen concentration in the gas atmosphere on the basis of the transmitted light intensity detected by the transmitted light intensity detector, and, if the first hydrogen concentration is in a first measurement range and the second hydrogen concentration is in a second measurement range, wherein the second measurement range has at least a part overlapping with the first measurement range, measurement value correction processing in which a weighted average value of the first hydrogen concentration and the second hydrogen concentration is calculated thereby to determine a measurement value of the hydrogen concentration in a range in which the first measurement range and the second measurement range overlap.