Hydrogen Generation Device, Operation Method Thereof, and Fuel Cell System

An operation method of a hydrogen generation device having a reforming unit generating a hydrogen-containing gas by steam-reforming of a raw material containing organic compounds composed of at least carbon atoms and hydrogen atoms, a raw material supply unit for supplying a raw material to the reforming unit, a steam generation unit for supplying steam to the reforming unit, a steam generation unit temperature detection unit for detecting a temperature of the steam generation unit and a heating unit which burns a mixture of fuel and air and supplies a combustion gas for successively heating the reforming unit and the steam generation unit by heat transfer,

• wherein any one of a rate supplied of an amount of the air to the heating unit, an amount of the fuel to the heating unit, and an amount of the water to the steam generation unit is controlled in such a way that a detected temperature of the temperature detection unit for a steam generation unit increases when the detected temperature is lower than a predetermined first threshold temperature, and wherein said any one of supplied amounts is controlled in such a way that a change per unit time in the detected temperature increases when a change per unit time in the detected temperature, which is derived from a first detected temperature detected by the temperature detection unit from a steam generation unit and a second detected temperature after a lapse of prescribed time, is lower than a first threshold value previously established with respect to change per unit time in the detected temperature.