The present invention relates to an electric power saving apparatus wherein light energy is irradiated to a semiconductor device, with the light energy emitted when a voltage is supplied to a transmission line, such that the wavelengths of the electrons on the transmission line, along which a load-driving current flows are elongated, and the spin motions and vibration states of the electrons are stabilized, thereby reducing the collision of electrons in order to reduce the loss of energy, and wherein the light energy irradiated to the semiconductor device is continuously supplied thereto, by the use of an infrared ray emitting diode during operation, thereby maintaining the power saving effects with stability and continuity.