Fuel cell stack

A fuel cell stack comprising a unit cell group, wherein the unit cell group includes: a plurality of unit cells (C1,C2,C3) connected in series; and at least one bypass resistor (BR1); wherein a respective said bypass resistor is connected in parallel with at least one of the said unit cells for providing a current path that bypasses the unit cell. According to the present invention, it is possible to prevent the fuel cell stack from being damaged and the performance from considerably decreasing, even if the performance of a unit cell decreases (or abnormally increases) or an electric short occurs in the fuel cell stack with a plurality of unit cells connected in series, in parallel, or in a series-parallel mixed type.