The invention provides a charging/discharging device which makes it possible to simultaneously charge and discharge a plurality of secondary batteries in parallel without using a power supply having extremely high current-supply capacity. The present invention is a charging/discharging device that simultaneously charges and discharges a plurality of charging/discharging bodies in parallel. Said charging/discharging device is provided with the following: charging power lines that provide supply power from a power-supplying means to each charging/discharging body; discharging power lines that provide discharged power from each charging/discharging body to the power-supplying means; a plurality of connection-switching means that are interposed between the charging power lines and discharging power lines and the plurality of charging/discharging bodies and that switch the connections between the charging power lines and discharging power lines and the plurality of charging/discharging bodies; and a switching-controlling means that controls the switching of the plurality of connection-switching means. The power-supplying means applies a plurality of different voltages, and the switching-controlling means controls the switching such that each charging/discharging body is connected to the plurality of charging power lines and the plurality of discharging power lines in turn in a prescribed order.