FUEL CELL SYSTEM

A fuel cell system (10) includes a fuel cell stack (116) and a control device (60). The control device (60) raises the voltage of the fuel cell stack (116) until a predetermined voltage condition is met, by supplying a cathode with an oxidant gas before current sweep is started when the fuel cell system (10) is started and a value measured by a temperature sensor (38) is equal to or less than a temperature determined in advance. The control device (60) executes stand-by control, in which a current command value is kept constant, when a measured voltage value reaches a control start voltage value smaller than a voltage command value in a transition period, and ends the stand-by control by permitting a change in the current command value when the measured voltage value reaches a permission voltage value equal to or more than the voltage command value during execution of the stand-by control.