Power controller, power conversion for converting a battery for supplying power to the electric motor of the electric vehicle of the plug-in type, a heating unit for heating the battery by heat generated by energizing the electric power supplied from an external power source and parts, based on the effective capacity in accordance with the temperature and the residual capacity of the storage battery, to infer the change in the effective capacitance at the time of raising the battery to the target temperature by heating by energization by the power supply of the heating unit from an external power source comprising a estimating unit, in response to a change in the effective capacity estimating unit is guessed, and a control unit for the power conversion unit controls the intended use of the electric power conversion.