[Object] To propose a power control device enabling a system that interchanges DC power to be realized with a simple configuration, and also enabling scalable construction of the system.[Solution] There is provided a power control device including a reception unit configured to receive a power supply demand from a cell connected to a first bus line that transmits direct-current (DC) power, a transmission unit configured to transmit, in response to the power supply demand from the cell connected to the first bus line that was received by the reception unit, the power supply demand to a cell connected to a second bus line that transmits DC power, and a power control unit configured to control, by a reply to the power supply demand transmitted to the cell connected to the second bus line, power conversion between the first bus line and the second bus line on a basis of information relating to respective voltages of the first bus line and the second bus line.