NOVELTY - A hydrogen generator (1) has hydrogen component (HC) storage unit (2), HC supplying unit (5), reactor (3) and vapor-liquid separating unit (4). The HC (30,30a) is contacted with metal supported catalyst (10) to generate hydrogen which is isolated and stored in buffer tanks. The booster pump (42) is provided in between buffer tanks, and pressure of buffer tanks (6,15) are adjusted.    USE - For electric power generating apparatus equipped with fuel cell apparatus, to generate electric power using hydrogen as raw material.    ADVANTAGE - The hydrogen generator suppresses pulsation of hydrogen generation quantity, and generates stabilized quantity of hydrogen with time, and has improved hydrogen-generating efficiency. The hydrogen generator is capable of fluctuating hydrogen supplying rate rapidly, and is highly dimensional and compatible.    DETAILED DESCRIPTION - A hydrogen generator (1) has hydrogen component storage unit (2), hydrogen component supplying unit (5), reactor (3), vapor-liquid separating unit (4), buffer tanks (6,15) and booster pump (42). The reactor is equipped with a heating device (11) and a metal supported catalyst (10). The hydrogen component contains hydrogenated derivative of an aromatic compound. The unit (2) accommodates hydrogen component (30,30a). The unit (5) supplies hydrogen component from the unit (2) to the reactor. The hydrogen component is contacted with metal supported catalyst in the reactor, and hydrogen is generated. The unit (4) isolates product (32) from the reactor into hydrogen (33) and liquid component (34). The isolated hydrogen is stored in the buffer tanks. The booster pump is provided in between the buffer tanks such that the pressure of inside portion of buffer tank (6) of stage (I) in which the isolated hydrogen is stored initially, is made into normal pressure or negative pressure, and pressure of inside portion of buffer tank (15) of last stage is made into high pressure.    DESCRIPTION OF DRAWING(S) - The figure shows model of the electric power generating apparatus having hydrogen generator.    Hydrogen generator (1)    Hydrogen component storage unit (2)    Reactor (3)    Vapor-liquid separating unit (4)    Hydrogen component supplying unit (5)    Buffer tanks (6,15)    Metal supported catalyst (10)    Heating device (11)    Hydrogen component (30,30a)    Product (32)    Hydrogen (33)    Liquid component (34)    Booster pump (42)