NOVELTY - A hydrogen generator comprises a reformer configured to generate a hydrogen-rich gas, a material feed system, a burner (2) to supply heat to reforming catalyst body (74) and an air supply system.    USE - For generating hydrogen-rich gas useful in a fuel cell system to generate power (claimed).    ADVANTAGE - The hydrogen generator is capable of stopping combustible gas combustion of the burner and efficiently post-processing the purge gas inside the burner. The fuel cell system can efficiently utilize the purge gas in fuel cell. The air can be supplied constantly from air supply stem to the burner thus processing of the purge can be maintained without fail. In the generator a hydrogen-rich reformed gas can be generated by a reforming reaction of the reforming catalyst body in a temperature range higher than the predetermined temperature thus it is possible to maintain the atmosphere surrounding the reforming catalyst body in a reduced state and supply of the water is stopped at the time when the predetermined temperature is reached, and therefore, steam condensation inside the reformer can be obviated. After putting out the flame of the burner, a hydrogen consumption rate may be controlled based on temperature of the reforming catalyst body. The hydrogen consumption rate is increased according to a decrease in the temperature of the reforming catalyst body. Thus, a desired power generation amount is maintained, the amount of wasted hydrogen can be reduced further since the proportion of hydrogen consumed increases, and cooling of the burner can be performed quickly.    DETAILED DESCRIPTION - An interior of the reformer is purged using the feed gas to shut down the hydrogen generator, then an amount of air supplied is increased to put out a flame of burner and a purge gas sent out from outlet port by the purging is mixed and diluted with air in burner and is discharged outside.    An INDEPENDENT CLAIM is included for a method of shutting down the hydrogen generator.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the burner and the periphery of the reforming catalyst body neighboring burner's combustion system.    Burner (2)    Flame region (67)    Combustion cylinder (68)    Combustion cylinder lid (71)    Reforming catalyst body. (74)