PURPOSE: To provide a fuel supply device for a fuel cell power generation device using methanol for material fuel with which methanol aqueous solution prepared for the material fuel can be used for combustion fuel for a methanol reformer without inconvenience.

CONSTITUTION: For a fuel cell power generation device which uses methanol for material fuel and generates power by supplying hydrogen reformed at a methanol reformer 2 to a fuel cell 1, methanol aqueous solution comprising metanol and water mixed in a predetermined ratio is stored in a material fuel tank, and methanol aqueous solution extracted from the material fuel tank is introduced to a reforming tube 2b of the methanol reformer. In the meanwhile, part of the extracted methanol aqueous solution is separated into high- concentration methanol and water through an organic solvent separation membrance (an aromatic polyimide hollow fiber membrane, for example), and obtained methanol is once stored in a methanol reservoir 13 to be supplied to a burner 2a of the methanol reformer 2 for combustion fuel when necessary.