It has been conventional that, when abnormality occurs in a device, the conditional operation of the device is further continued while neglecting the abnormality temporarily on condition that remedial action taken later by service staff. There has been no simple method to quickly remove slight failures, etc. included in the abnormality. A fuel cell power generation system comprises a fuel cell (21), fuel gas supply means (22), oxidizing agent gas supply means (34), condition detection means (42) for measuring the temperature of the fuel gas supply means (22), operation control means (47) for detecting abnormality of a specific function of the fuel cell supply means (22) using the result of detection by the condition detection means (42) and conducting operation control in an operation mode corresponding to the content of the abnormality, and operation mode switching means (44) for switching the operation mode to a mode corresponding to the content of the abnormality.