To reduce energy required for preventing freezing of a fuel cell power generation device.

The fuel cell power generation device includes a casing 11 in which an air suction port 12 and an exhausting port 22 are formed; a fuel cell 21 housed in the casing 11; and a ventilation fan 15 for exhausting gas in the casing 11 from the exhausting port 22. An electric heater 13 and a control means are installed in the fuel cell power generation device. The electric heater 13 heats gas introduced from the air suction port 12. The control means is a temperature sensor 14 such as a thermostat, measures the temperature of the inside of the casing 11, and when the measured temperature is equal to or lower than the prescribed reference temperature, operates the electric heater 13 and reduces the exhaust speed of gas exhausted by the ventilation fan 15 when the ventilation fan 15 is operated.