A charging system of an electric vehicle, comprising: a drive battery which stores electric power for driving a motor of the electric vehicle; a heater which heats the drive battery; an electric power supply device (21, 22) which converts electric power supplied from outside the electric vehicle (31, 32) and supplies the electric power to the drive battery or the heater; a contactor which activates or deactivates a connection between the drive battery and the electric power supply device; temperature detection means which detects a temperature of the drive battery; and control means which controls the contactor and the heater based on the temperature detected by the temperature detection means, wherein the control means controls the contactor so as to deactivate the connection and conducts electricity to the heater when the temperature of the drive battery is less than a first predetermined temperature (a), and controls the contactor so as to activate the connection when the temperature of the drive battery is the first predetermined temperature or greater. Wherein the electric power supply device includes: a charger which converts the electric power supplied from outside the electric vehicle and supplies the converted electric power to the drive battery; and a voltage convertor which is connected to the charger, which converts voltage of the electric power converted by the charger, characterized in that the charging system further comprises an auxiliary battery which supplies electric power to the heater; and a charge amount detection means which detects a charge amount of the auxiliary battery, wherein the voltage convertor supplies the voltage to the auxiliary battery, the heater includes a plurality of heaters which can be activated or deactivated individually, or includes a variable resistance heater, so as to change heater output; and the control means changes the heater output according to the charge amount of the auxiliary battery. a drive battery which stores electric power for driving a motor of the electric vehicle; a heater which heats the drive battery; an electric power supply device (21, 22) which converts electric power supplied from outside the electric vehicle (31, 32) and supplies the electric power to the drive battery or the heater; a contactor which activates or deactivates a connection between the drive battery and the electric power supply device; temperature detection means which detects a temperature of the drive battery; and control means which controls the contactor and the heater based on the temperature detected by the temperature detection means, wherein the control means controls the contactor so as to deactivate the connection and conducts electricity to the heater when the temperature of the drive battery is less than a first predetermined temperature (a), and controls the contactor so as to activate the connection when the temperature of the drive battery is the first predetermined temperature or greater. controls the contactor so as to deactivate the connection and conducts electricity to the heater when the temperature of the drive battery is less than a first predetermined temperature (a), and controls the contactor so as to activate the connection when the temperature of the drive battery is the first predetermined temperature or greater. Wherein the electric power supply device includes: a charger which converts the electric power supplied from outside the electric vehicle and supplies the converted electric power to the drive battery; and a voltage convertor which is connected to the charger, which converts voltage of the electric power converted by the charger, a charger which converts the electric power supplied from outside the electric vehicle and supplies the converted electric power to the drive battery; and a voltage convertor which is connected to the charger, which converts voltage of the electric power converted by the charger, an auxiliary battery which supplies electric power to the heater; and a charge amount detection means which detects a charge amount of the auxiliary battery, wherein the voltage convertor supplies the voltage to the auxiliary battery, the heater includes a plurality of heaters which can be activated or deactivated individually, or includes a variable resistance heater, so as to change heater output; and the control means changes the heater output according to the charge amount of the auxiliary battery.