To provide an explosion-proof gas heating device and method, capable of heating a combustible gas without the risk of explosion.

Two sets of heaters, comprising a heat storage chamber connected with a combustible gas (H2) supply source and a combustible gas supply destination and two heat storage chambers provided with a burner and connected with the heat storage chamber and an inert gas (N2) supply source, are provided. When the combustible gas that is heated is supplied from the heat storage chamber of one heater, either burner of the other heater is burned. At the same time, exhaustion is carried out, so as to perform the thermal storage of the heat storage chamber, and the exhaust of the heat storage chamber connected with the combustible gas supply destination is performed, while supplying the inert gas to the heat storage chamber that has been already provided with thermal storage by the burner to perform the thermal storage of the heat storage chamber. Then, the combustible gas is supplied to this heat storage chamber to heat it and is supplied to the combustible gas supply destination. While this is repeated alternately, the combustible gas that is continuously heated is supplied.