A charging system for an electrically driven vehicle, provided with an electric motor, a battery for supplying electrical power to the electric motor, the charging system comprising: a charger for charging the battery by using electrical power supplied from outside; a charging control section for controlling operation of the charger; and a thermometer for measuring the temperature of the battery; characterized in that the vehicle is an operation machine comprises further a hydraulic pump for discharging hydraulic oil, a hydraulic actuator driven by the hydraulic oil discharged from the hydraulic pump, an operation device for performing a predetermined operation by using operation of the hydraulic actuator, that the charging system comprises an internal clock; and that the charging control section is adapted to control operation of the charger so that, - in a case in which operation of the electric motor is at a stop - when the internal clock indicates that time is outside of a predetermined time frame, - charging of the battery is performed to radiate heat until the temperature of the battery exceeds the predetermined temperature when the temperature of the battery is equal to or less than the predetermined temperature, and - charging of the battery is stopped when the temperature of the battery exceeds a predetermined temperature, and - when the internal clock indicates that time is within the predetermined time frame, charging of the battery is performed until the battery is charged. a charger for charging the battery by using electrical power supplied from outside; a charging control section for controlling operation of the charger; and a thermometer for measuring the temperature of the battery; characterized in that the vehicle is an operation machine comprises further a hydraulic pump for discharging hydraulic oil, a hydraulic actuator driven by the hydraulic oil discharged from the hydraulic pump, an operation device for performing a predetermined operation by using operation of the hydraulic actuator, that the charging system comprises an internal clock; and that the charging control section is adapted to control operation of the charger so that, - in a case in which operation of the electric motor is at a stop - when the internal clock indicates that time is outside of a predetermined time frame, - charging of the battery is performed to radiate heat until the temperature of the battery exceeds the predetermined temperature when the temperature of the battery is equal to or less than the predetermined temperature, and - charging of the battery is stopped when the temperature of the battery exceeds a predetermined temperature, and - when the internal clock indicates that time is within the predetermined time frame, charging of the battery is performed until the battery is charged. - in a case in which operation of the electric motor is at a stop - when the internal clock indicates that time is outside of a predetermined time frame, - charging of the battery is performed to radiate heat until the temperature of the battery exceeds the predetermined temperature when the temperature of the battery is equal to or less than the predetermined temperature, and - charging of the battery is stopped when the temperature of the battery exceeds a predetermined temperature, and - when the internal clock indicates that time is within the predetermined time frame, charging of the battery is performed until the battery is charged.