Abstract: An electrical vehicle energy supply system has an electrical vehicle which carries in a prescribed location a freely removable cassette-type battery and an energy supply station which has at all times a plurality of the cassette-type batteries and which performs charging processing of units of these batteries which include the number of batteries required by one such electrical vehicle, and performs the function of storing said batteries in a fully charged condition. In this system, when an electrical vehicle enters the energy supply station, all of the batteries are removed therefrom, these being replaced by an equal number of fully charged batteries that had been stored at the energy supply station, the single or multiple batteries that had been removed from the electrical vehicle being charged, the electrical vehicle heading toward a next energy supply station and the energy supply station awaiting the arrival of a next electrical vehicle.