NOVELTY - The noble metals are provided down stream to the reforming and the transformation units (1,2). The carbon monoxide removal unit (3) has CO removal catalyst and the water vapor feed zone (7) supplying water vapor to the reforming unit are provided up stream to the reforming unit. The fuel feed zone (5) and air feed zone (6) provided upstream to the catalyst combustion unit (4), respectively supply hydrocarbon type fuel and air to the catalyst combustion unit.    USE - For supplying hydrogen to fuel cell.    ADVANTAGE - The apparatus is simplified. The transferring time from starting condition to the steady state is reduced by simple operation. The transferring operation from steady state to stopping is smooth, and excellent in safety. Hydrogen generator is excellent in operativity and efficiency.    DETAILED DESCRIPTION - A flame combustor is provided upstream to the reforming unit for pre-heating the catalyzed combustion unit. The amount of supply of air or hydrocarbon type fuel is controlled so that air-fuel ratio approximately becomes the stoichiometry equivalent ratio of the combustion reaction. Sensors detects the temperatures of reforming and catalyst combustion units and the amount of supply of hydrocarbon fuel and air is stopped when the detected temperatures are less than predetermined value. The supply of hydrocarbon type fuel is started after supplying air for a predetermined time, when the detected temperature of catalyst combustion unit after pre-heating exceeds the predetermined value. Water vapor is supplied when the fuel in the air-fuel ratio exceeds the range, during starting. The CO removal catalyst utilizing heat of modified catalyst rises the temperature of modified catalyst to a predetermined temperature.    INDEPENDENT CLAIMS are also included for the following:    (a) Starting method of hydrogen generator;    (b) Stopping method of hydrogen generator    DESCRIPTION OF DRAWING(S) - The figure shows the flow path of the hydrogen generator. (Drawing includes non-English language text).    Transformation units (1,2)    Carbon monoxide removal unit (3)    Catalyst combustion unit (4)    Fuel feed zone (5)    Air feed zone (6)    Water vapor feed zone (7)