This fuel cell system comprises: a fuel cell including a membrane-electrode assembly formed by disposing electrodes having a catalyst layer on both sides of a polymer electrolyte membrane; and a control device for controlling the output voltage of the fuel cell. When a target voltage for the fuel cell is set to greater than or equal to a catalyst elution voltage at which a catalyst in the catalyst layer is eluted and it is estimated that the amount of oxide film formed on the catalyst layer is less than a first predetermined amount, the control device performs control so that the output voltage of the fuel cell reaches an oxide film formation voltage lower than the catalyst elution voltage until it is estimated that the amount of oxide film has reached the first predetermined amount or more, and then performs control so that the output voltage of the fuel cell reaches the target voltage.
