PURPOSE: To minimize the loss of the title mechanism including a dynamotor connected with a fly wheel, by starting to store electric power when an electric car is detected, and permitting the electric power to be released when the electric car is moved away from the detector and reaches the electric power regenerative apparatus.

CONSTITUTION: The electric car detector 18 is positioned at a distance (d) from the electric power regenerative apparatus 18 along an electric-car line 11, the storing is started from the point where the electric car 17a has passed the electric car detector 18, and the stored electric power is released when th electric car 17b reaches a point adjacent the electric power regenerative apparatus 18 so that the electric power is supplied to the electric car. Based upon the signal from the electric car detector 18, the electric power regenerative apparatus 13 is controlled by a supplementary apparatus 16. Therefore, since the electric power regenerative apparatus 13 can store a required amount of the electric power when required, the loss which will occur in the apparatus 13 itself can be minimized.