The invention relates to a fuel cell system. The fuel cell system includes a drive motor 17, a fuel cell 14, an auxiliary machine 18, a secondary battery 12, a temperature sensor T, a current sensor IB, and a control section 11. The control section 11 controls the secondary battery 12 for discharging by driving the drive motor 17 or the auxiliary machine 18 and for charging through power generation by the fuel cell 14 or regeneration by the drive motor 17 when a temperature measured by the temperature sensor T is lower than a specified value.