A method of manufacturing methanol comprising producing a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide, allowing reaction of the synthesis gas to take place over a catalyst to produce a crude methanol, separating the crude methanol into unreacted gas and liquid crude methanol, and distilling the liquid crude methanol to separate it into refined methanol and waste water. Carbon dioxide in combustion exhaust gas to be discharged from a reformer is recovered, and that in feeding the carbon dioxide to the upstream side and/or the downstream side of the reformer, part of the unreacted gas is utilized as a purge gas, a portion of which being utilized as a fuel for a combustion device of the reformer, while the balance of the purge gas being utilized as a fuel for other heating sources and/or as an agent for desulfurizating raw gas.