To provide a method of generating an atmospheric gas for high temperature rapid carburization capable of stably generating a reformed gas containing high concentration of carbon monoxide suitable as the atmospheric gas for high temperature rapid carburization while avoiding the risk of explosion accompanying the use of oxygen and suppressing the generation of soot.

This method comprises the steps of squirting hydrocarbon and oxygen, and if necessary, carbon dioxide and steam into the combustion chamber from each nozzle to form a gas mixture, and incompletely combusting the mixed gas to generate the atmospheric gas for high temperature rapid carburization containing carbon monoxide and hydrogen as main components together with carbon dioxide and steam.