PURPOSE: To provide a tire vulcanizing method wherein the temperature difference between upper and lower parts of a green tire can be eliminated as much as possible when inert gas such as nitrogen gas is used together with steam for heating and pressing the green tire.

CONSTITUTION: Two processes are provided. In the first process, a steam S of a predetermined pressure is made to blow in a green tire T, which is heated and pressed. In the second process, an inert gas N such as a nitrogen gas having higher pressure, lower temperature, and heavier specific gravity than that of the steam S is made to blow in so as to be added to the steam S and the green tire T is filled with a first mixed gas of the steam S and the inert gas N, which is mainly pressed. A flow which makes the inert gas N blow in and discharges the first mixed gas by opening a discharge opening is generated in the green tire T. Also, a process for filling the green tire T with a second mixed gas wherein the ratio of the inert gas N is heighten is provided.