Hydrogen gas production device

A hydrogen gas production apparatus comprising:

• a vaporizer configured to generate ammonia gas by heating liquid ammonia;
• a main thermal decomposition device configured to decompose the ammonia gas generated in the vaporizer, into nitrogen gas and hydrogen gas, by heating the ammonia gas by causing a fuel gas to burn;
• a cooler configured to cool a first decomposition gas including the nitrogen gas and the hydrogen gas generated through the decomposition in the main thermal decomposition device;
• and
• a separator configured to separate hydrogen gas from the first decomposition gas having been cooled,
• wherein the cooler is configured to cool the first decomposition gas by allowing heat exchange between the liquid ammonia before being introduced into the vaporizer and the first decomposition gas, and
• the vaporizer generates ammonia gas by heating the liquid ammonia having undergone the heat exchange in the cooler.