METHOD FOR OPERATING A HYDROGEN GENERATION DEVICE AND FUEL CELL SYSTEM

A hydrogen generator of the present invention comprises a reformer (1) including a reforming catalyst (1A) which allows a hydrogen-containing gas to be generated using a raw material and steam; a water evaporator (3) for generating the steam; a raw material supply passage (2) which supplies the raw material to the reforming catalyst (1A) of the reformer (1); a steam supply passage (4) which supplies the steam generated in the water evaporator (3) to the reforming catalyst (1A) of the reformer (1); a pressure releasing device (6) provided at the raw material supply passage (2) or the steam supply passage (4); an exhaust passage (7) which flows a gas exhausted from the pressure releasing device (6) and containing the steam; and a cooler (8) provided at the exhaust passage and configured to cool the gas.