To provide a producing method of hydrogen from methanol and its device by which hydrogen gas of high purity can be recovered with high recovering efficiency.

Methanol and pure water as the source material are deaerated in deaerating towers 10, 13. The deaerated methanol and pure water are mixed, preliminarily heated and then vaporized in a vaporizing device 4 to produce a mixet gas of methanol and water vapor. The mixet gas is introduced into a reactor 1, where the mixet gas is reformed into hydrogen and carbon dioxide by the catalyst in the reactor 1. The reformed gas is subjected to heat exchange with the mixet liquid of methanol and pure water, and then cooled. The cooled reformed gas is subjected to gas-liquid separation in a gas-liquid separator 12a. The reformed gas after the gas-liquid separation is decomposed in a PSA device 17 to separate and recover the hydrogen gas.