In order to provide a hydrogen sensor for measuring a hydrogen concentration with high sensitivity and excellent mass-productivity, the hydrogen sensor includes: at least a first quartz vibrator and a second quartz vibrator formed in a quartz plate; a hydrogen reaction catalytic layer including a platinum film of platinum black formed on both sides of the first quartz vibrator; and a hydrogen non-reactive layer formed in the second quartz vibrator, wherein a hydrogen concentration is measured by measuring a temperature of the first quartz vibrator increasing by heat of combustion caused by oxidization of hydrogen by the hydrogen reaction catalytic layer as a change of a natural frequency of the first quartz vibrator with respect to a natural frequency of the second quartz vibrator.