A charge/discharge control apparatus includes: a charge/discharge reward information receiving unit for receiving charge/discharge reward information representing a reward given to a charge/discharge action of a customer and a restriction in conducting a charging/discharging from a charge management central server; a computing unit for creating a charge/discharge plan including a total charging quantity in a time zone and an estimated use start time of an electric vehicle such that a reward is maximized, based on the charge/discharge reward information; a charge/discharge instruction transmitting unit for instructing the electric vehicle to start or finish a charging/discharging according to the charge/discharge plan; a charge/discharge quantity monitoring unit for monitoring the charging/discharging; and a charge/discharge results transmitting unit for transmitting results of monitored charging/discharging including contents of the conducted charging/discharging and individual identification information for identifying itself, to a charge management central server.