FUEL CELL SYSTEM

PROBLEM TO BE SOLVED: To provide a technique related to a fuel cell system.SOLUTION: A fuel cell system comprises: a fuel cell; a gas supply section that supplies cathode gas; a supply passage through which the cathode gas is circulated from the gas supply section to the fuel cell; a discharge passage through which cathode off-gas discharged from the fuel cell is circulated; a back pressure adjustment section that adjusts back pressure of the cathode off-gas; a bypass passage through which the cathode gas bypasses the fuel cell and is circulated from the gas supply section to the discharge passage; a switching section that switches between the supply passage and the bypass passage so as to circulate the cathode gas supplied from the gas supply section, through any one of the supply passage and the bypass passage; a temperature detecting section that detects the temperature of the cathode gas supplied from the gas supply section; and a control section that controls the switching section in such a manner that the cathode gas is circulated through the bypass passage, when the back pressure adjustment section increases the back pressure and the temperature detecting section detects that the temperature of the cathode gas exceeds a predetermined temperature.