A power transmission system includes: a power transmitter connected to a power supply; a plurality of power receivers respectively connected to a plurality of loads; a power transmission line connecting the power transmitter and the plurality of power receivers; and a controller. The controller acquires information on optimum power for maximizing transmission efficiency in the power transmission line and information on power demands requested by the loads, and routes transmission power from the power transmitter selectively to the plurality of power receivers. The transmission power is equal to or smaller than the optimum power. When a total power demand is larger than the optimum power, the controller requests another controller to supply supplementary power. When the total power demand is smaller than the optimum power, the controller notifies the other controller that surplus power is available.