A battery charging system, comprising: an electric vehicle; a network termination unit connectable to the electric vehicle through a power line cable for supplying electric power to the electric vehicle; a first server that transmits a control signal indicative of permission or forbiddance of power supply from the network termination unit to the electric vehicle to the electric vehicle through the network termination unit; and a second server, characterized in that: the electric vehicle transmits identification information for identifying the electric vehicle and a user thereof to the first server through the network termination unit, the identification information comprising a user identifier and the vehicle number, the network termination unit transmits position information concerning a position of the network termination unit to the first server, the first server authenticates the electric vehicle and the user thereof based on the vehicle number and the user identifier, respectively, and determines permission or forbiddance of the power supply based on a result of vehicle and user authentication or the position information, the electric vehicle transmits an emergency signal to the second server in an emergency, and the second server determines whether or not it is an emergency based on the position information, weather information, accident information and traffic information at a place from which the emergency signal is transmitted, and transmits a control signal indicative of permission of the power supply to the electric vehicle upon receiving the emergency signal and determining that it is an emergency, regardless of a result of user authentication. an electric vehicle; a network termination unit connectable to the electric vehicle through a power line cable for supplying electric power to the electric vehicle; a first server that transmits a control signal indicative of permission or forbiddance of power supply from the network termination unit to the electric vehicle to the electric vehicle through the network termination unit; and a second server, the electric vehicle transmits identification information for identifying the electric vehicle and a user thereof to the first server through the network termination unit, the identification information comprising a user identifier and the vehicle number, the network termination unit transmits position information concerning a position of the network termination unit to the first server, the first server authenticates the electric vehicle and the user thereof based on the vehicle number and the user identifier, respectively, and determines permission or forbiddance of the power supply based on a result of vehicle and user authentication or the position information, the electric vehicle transmits an emergency signal to the second server in an emergency, and the second server determines whether or not it is an emergency based on the position information, weather information, accident information and traffic information at a place from which the emergency signal is transmitted, and transmits a control signal indicative of permission of the power supply to the electric vehicle upon receiving the emergency signal and determining that it is an emergency, regardless of a result of user authentication.