The invention relates to the field of electrical engineering, in particular to electrotechnical components, and in this specific case to polar capacitors with a fixed capacitance. The technical result of the use of the invention consists in the possibility of producing electrical energy stores with small dimensions and high capacitance and voltages. The vacuum capacitor comprises an anode arranged outside a vacuum chamber, in which a cathode is arranged as well as a dielectric, between said cathode and anode. Said cathode can be designed in such a way that it can be heated by means of an electrically insulated filament disposed in the vacuum chamber, said vacuum chamber being in the form of a dielectric hermetically sealed cylinder, and said anode is arranged on the outer surface of the dielectric hermetically sealed cylinder. The cathode can be a “cold” cathode with a micropeak-type surface, which enables the loss of free electrons from the surface thereof without any heating, and the anode is located on the outer surface of the dielectric cylinder with a high vacuum and a cathode arranged therein.