Abstract: The inspection method for a fuel cell stack including a plurality of unit cells comprises: (a) operating a fuel cell system, including the fuel cell stack and an anode gas circulation flow path that is connected between an anode gas discharge port and an anode gas supply port of the fuel cell stack to circulate anode gas, under a predetermined liquid water accumulation condition to accumulate liquid water in the anode gas circulation flow path; (b) causing, after the step (a), the fuel cell system to stop and stand by until a predetermined restarting condition is satisfied; and (c) restarting, after the step (b), the fuel cell system to implement power generation by the fuel cell stack, and measuring voltage of each of the unit cells to detect a unit cell having negative voltage.