HYDROGEN CONCENTRATION MEASURING DEVICE, HYDROGEN CONCENTRATION MEASURING METHOD, AND HYDROGEN CONCENTRATION DISPLAY DEVICE

PROBLEM TO BE SOLVED: To allow sensing of hydrogen concentration in a wide range area and to allow accurate sensing of hydrogen concentration even when a mechanical vibration or a vibration due to an earthquake is present.SOLUTION: In a hydrogen concentration measuring method, a hydrogen concentration is measured based on an amount of strain occurring in an optical fiber due to a change in a hydrogen sensing substance attached to the optical fiber. When an amount of strain corresponding to the hydrogen concentration which is to be measured based on the change in the hydrogen sensing substance is mixed with an amount of strain which occurs constantly or temporarily due to a vibration applied to the optical fiber, the amount of strain occurring due to the vibration is eliminated by executing filter processing on time-series measurement result of amount of strain measured by the optical fiber, and the hydrogen concentration is measured by using only the amount of strain corresponding to the hydrogen concentration.