Abstract: A electron-beam tube comprises a cathode (2) made as individual tapes (6) disposed throughout the length of the tube, whose surfaces are the emitting portions of the cathode (2). Each tape (6) of the cathode (2) is provided with a near-cathode focusing electrode (9) electrically connected to the cathode (2) and disposed in the immediate vicinity of the tape (6), and with a pair of rods (10) of the control electrode (3) disposed in relation to the tape (6) so that the whole electron flow focused by the near-cathode electrode (9) passes between said rods (10). The following relations are observed in the tube:a/b=c/d; 1<d/c.ltoreq.10; e.gtoreq.b.