FUEL CELL SYSTEM

PROBLEM TO BE SOLVED: To provide a fuel cell system having high reliability eliminating liquid drop detention in a fuel gas flow passage beforehand without requiring a number of additional parts, restraining deterioration of a fuel cell. SOLUTION: The fuel cell system comprises a fuel cell stack 45 generating power by the supply of hydrogen and air, a hydrogen supply system supplying hydrogen to the fuel cell stack 45, an air supply system supplying the air to the fuel cell stack 45, and a hydrogen circulation system circulating the hydrogen not consumed at the fuel cell stack 45 to the hydrogen supply system through a hydrogen circulating pump 7. The rotation number of the hydrogen circulating pump 7 is increased by a controller 50, when an operation period of the hydrogen circulating pump 7 after its rotation number has exceeded a prescribed rotation number exceeds a prescribed period, independent from take-out load of the fuel cell stack 45. COPYRIGHT: (C)2007,JPO&INPIT