Some energy is lost from an operating machine by all means. In this research, the energy that is lost by the intention of the manipulator of the machine is defined as the artificially discarded energy. Then a way to recover the artificially discarded energy from an operating machine as the potential energy is discussed. In this paper, the basic mechanism to recover the kinetic energy of a vehicle reducing speed by braking as the potential energy into a spiral spring was proposed and the prototype of it was made. The preserved energy in the spiral spring will be regenerated as the kinetic energy again of the vehicle when the vehicle begins moving. The flow of the energy is shown and the recovery efficiency and the regeneration efficiency are discussed by some basic experiments.