PURPOSE: To provide a methanol-switching fuel cell power generator capable of smoothly switching the fuel even from the normal liquid state of methanol.

CONSTITUTION: A methanol evaporator 30 covered its circumference with a heat-insulation material contains a methanol sprayer 33 at the upper part and a heat-exchanger 34 to heat the mist generated by the methanol sprayer 33 in the middle part of the evaporator. A heat-exchanger 19 is permanently connected to the outlet of a cooler 18 of the main body 12 of the fuel cell. Hot water branched from the outlet of the heat-exchanger 19 is supplied to the heat-exchanger 34 through a hot water line 35 to heat the exchanger. The methanol sprayer 33 is supplied with liquid methanol 23 pumped up from a methanol storage tank 31 with a methanol supplying pump 36 in the case of switching the fuel. The methanol vapor generated in the methanol evaporator 30 is supplied to an ejector 7 via a methanol vapor supply line 39. A reformer 32 is provided with an exclusive burner for methanol liquid and the methanol liquid 23 branched from the methanol evaporator 30 is ejected in the case of switching the fuel.