A charging system for a storage battery, includes: a storage battery which supplies power to a motor which is a drive source for a plug-in electric vehicle; a power conversion unit which converts power supplied from an external power source and supplies the converted power to at least the storage battery; a flow path which is attached to the storage battery and the power conversion unit and through which heat medium for adjusting temperatures of the storage battery and the power conversion unit flows; a heating unit for heating the heat medium; a temperature detector for detecting the temperature of the storage battery; and a control unit which performs control to supply the converted power to the storage battery and the heating unit when the temperature of the storage battery is below a predetermined threshold value.