An electron beam device having a tubular body of elongate shape with an electron exit window extending in the longitudinal direction of the tubular body. The tubular body is at least partly forming a vacuum chamber, the vacuum chamber comprising therein a cathode comprising a cathode housing having an elongate shape, and at least one electron generating filament and a control grid both extending along the elongate shape of the cathode housing. The control grid and the cathode housing are attached to each other by attachment mechanisms. Free longitudinal end portions of either the control grid or the cathode housing are bent in a direction towards each other to form bulge-like shapes for the formation of electron beam shaping electrodes. The invention is further comprising a method of manufacturing the electron beam device.