To prevent insufficiency of the electric energy by regulating the pressure in a fuel tank.

In a hybrid automobile, when the voltage E of a low-voltage battery exceeds the caution-needed reference value Eth1, a negative pressure pump is operated by the regular power consumption (Step S120). When the voltage E exceeds the low-charging reference value Elow but below the caution-needed reference value Eth1, the negative pressure pump is operated by the power consumption smaller than the regular value (Step S130). When the voltage E is determined to be lower than the low-charging reference value Elow, the operation of the negative pressure pump is stopped (Step S135). Therefore, when the pressure regulation in a fuel tank is completed, the voltage of at least the low-charging reference value Elow can be accumulated in the voltage E of the low-voltage battery, and insufficiency of the electric energy can be prevented by regulating the pressure in the fuel tank.