A solar energy converter includes: a light-concentrating instrument; an electron emitter in an insulated vacuum vessel, emitting electrons in a vacuum as a temperature rises by sunlight; an electron accelerator within the light-concentrating instrument; a cathode on a surface of the electron emitter opposite to a surface which is irradiated by sunlight, and electrically connected with the electron emitter; an electric field supplier having a positive terminal and a negative terminal; and an electron collector in the vacuum vessel, collecting the emitted electrons flying from the electron emitter toward the electron accelerator; wherein the electron accelerator is connected with the positive terminal and the cathode is connected with the negative terminal to generate an electric field, and the electron collector is used as a negative generator electrode and the cathode is used as a positive generator electrode in which the collected electrons migrate to the electron emitter to generate electricity.