Methods for production of synthesis gas

Disclosed is a syngas production method that reduces the deposition of carbon on a catalyst without increasing the amount of the starting gas unnecessarily. Specifically disclosed is a method for generating syngas that comprises hydrogen and carbon monoxide by introducing a hydrocarbon gas, an oxygen gas and a carbonic acid gas and inducing a combustion reaction and a reforming reaction by means of a catalytic reaction with a catalyst, said method involving a temperature increasing process for increasing the temperature on the interior of a reformer to a prescribed startup initiation temperature, a carbonic acid gas introduction initiation process for initiating the introduction of a carbonic acid gas into the heated reformer, a hydrocarbon gas introduction process for introducing a hydrocarbon gas into the reformer, an oxygen gas introduction process for introducing oxygen gas into the reformer. During the carbonic acid gas introduction initiation process, the amount of carbonic acid gas introduced is increa