A hydrogen generating device can decompose fuel containing an organic compound at low temperature to generate hydrogen-containing gas that scarcely contains nitrogen and carbon monoxide without providing electric energy from outside or by providing only a small amount of electric energy from outside.The hydrogen generating device for generating hydrogen-containing gas by decomposing fuel containing an organic compound is characterized by comprising a hydrogen generating cell (10) formed by sandwiching a bonded assembly including a partition membrane (11), a fuel electrode (12) arranged on one of the surfaces of the partition membrane (11) and an oxidizing electrode (14) arranged on the other surface of the partition membrane (11) between a fuel electrode separator provided with a channel groove (13) for flowing fuel containing an organic compound and water to the fuel electrode (12) and an oxidizing electrode separator provided with a channel groove (15) for flowing an oxidizing agent to the oxidizing electrode (14), a means (16) for supplying fuel containing the organic compound and water to the fuel electrode (12), a means (17) for supplying an oxidizing agent to the oxidizing electrode (14) and a means (23) for generating and collecting the gas containing hydrogen from the fuel electrode (12). The hydrogen generating device may be (a) an open circuit that does not withdraw electric energy to outside from the hydrogen generating cell (10) of the hydrogen generating device and does not provide electric energy from outside to the hydrogen generating cell, (b) a device adapted to withdraw electric energy to outside with the fuel electrode (12) and the oxidizing electrode (14) respectively as negative electrode and positive electrode or (c) a device adapted to provide electric energy from outside with the fuel electrode (12) and the oxidizing electrode (14) respectively as cathode and anode.