According to some embodiments, there is provided a controller that performs communication with a plurality of power supply units each of which outputs electric power to a load. The controller includes a receiving unit, a control information generating unit and a transmitting unit. The receiving unit receives operation information from the power supply units by radio, the operation information being information on electric power output to the load from the power supply units, respectively. The control information generating unit generates control information to control the power supply units based on the operation information. The transmitting unit transmits the control information to the power supply units by radio.