The usage pattern of an electric vehicle including the amount of power consumption of a battery on each day of the week is extracted from usage histories of the vehicle in a predetermined period. When the vehicle goes home after one day's operation and is connected to a charging apparatus, a charge determination unit predicts a usage pattern of the vehicle on the next day and determines whether the vehicle can operate on the next day with the remaining amount of power of a battery in the vehicle. When it is determined that the charging of the battery is necessary, the battery is charged until it reaches the target remaining amount of power. The target remaining amount of power is determined on the basis of the amount of power consumption in the predicted usage pattern so that the full charge is prevented and the number of charges is reduced.