Thermionic solar converter with a linear arrangement of the components, suitable for the direct conversion of solar energy into electrical energy and the combined generation of heat and energy, in the form of an elongated transparent vacuum tube comprising: a cathode (5) and at least one anode (6), said cathode and anode being arranged longitudinally alongside each other along the tube: grid electrodes (10, 11, 13, 14, 15, 16) for generating electric fields; means (18) for directly cooling the at least one anode; means (7) for electrically connecting the electrodes from the inside to the outside; an optical access window (4) along the surface area of the tube; wherein: the cathode is made of conductive refractory material, is suspended centrally inside the tube with an elongated form and forms the element for capturing the solar energy, on which the sunlight is directly focused in order to perform the thermionic conversion, without any intermediate heat transfer means; the electrical connection means form a longer path and have a form which is able to compensate for the heat expansion; the cathode and the at least one anode have a relative arrangement with a view factor of between 0.001 and 0.5, more preferably between 0.001 and 0.3, more preferably between 0.001 and 0.1, more preferably between 0.001 and 0.05, even more preferably between 0.001 and 0.03; said converter comprising further a radiation shield (9) which is positioned along the inner surface of the tube.