<p>A magnetron device comprising a magnetron body having a cathode stem and an output antenna section respectively provided projectively from both ends of said body, first and second magnets disposed on the magnetron body with the projecting cathode stem and output antenna section respectively inserted into the magnets and a yoke for magnetically connecting the first and second magnets. The first magnet mounted on the cathode stem side bears a substantially parallelepiped form almost as wide as the outer diameter of the magnetron body and the second magnet provided on the output antenna side presents a thin doughnut shape. That side of the yoke which faces the first magnet is made substantially as wide as the end face of the first magnet and the magnetron body is provided with a plurality of radiator plates erected on the magnetron body in a radial direction, each having a plane parallel with the axis of the magnetron body.</p>
