Apparatus for generating hydrogen

An apparatus for generating hydrogen gas in which hydrogen gas of a high purity is supplied to a hydrogen-utilizing device by using a decahydronaphthalene/naphthalene reaction. The apparatus includes a storage tank (10) in which decahydronaphthalene is stored as a crude fuel, a reaction tank (20) which has a catalyst and a heater (22) for heating the catalyst and which causes dehydrogenation of decahydronaphthalene supplied from the storage tank to the heated catalyst, and a separation tank (30) in which hydrogen-rich gas is separated out from naphthalene and hydrogen gas supplied from the reaction tank by using a hydrogen separation film and from which the separated hydrogen gas is discharged.