To provide a hydrogen generation system which generates a stable amount of hydrogen with time.

The hydrogen generation system 1 generates hydrogen 33 by bringing a hydrogen donor 30 containing a hydrogenated derivative of an aromatic compound into contact with a supported metal catalyst 10. The system is equipped with a hydrogen donor storage means 2 for housing the hydrogen donor 30, a reactor 3 having the metal catalyst 10 in a manner enabling its contact with the hydrogen supply body 30 and a heating means 11 for heating the metal catalyst 10, and a gas-liquid separation means 4 for separating a product 32 produced in the reactor 3 into hydrogen 33 and a liquid component 34. The system has a structure wherein the liquid component 34 separated by the gas-liquid separation means 4 flows into the storage means 2 as the hydrogen donor and wherein the supply rate of the hydrogen donor supplied to the reactor 3 is changed according to the concentration of "the hydrogenated derivative of the aromatic compound" in the hydrogen donor at a predetermined position.