In a directly heated meshed cathode made of one metal piece in the form of a hollow cylinder, the working surface is constituted by intersecting helical filaments 3 and 4 with holes 5 therebetween, each filament 3 and 4 being formed with a stepped increase in the width from periphery to center of the cathode. A method of making the meshed cathode comprises fabrication of a tool electrode out of a plate by electroerosive cutting of grooves in the end portion of the plate with projections therebetween shaped to match the holes 5 between the filaments 3 and 4, and electroerosive broaching, using this tool electrode, of longitudinal rows of holes 5 in a hollow cylindrical blank rotatably displaced, after each pass of the tool electrode, through an angle equal to twice the angular distance between the center lines of adjacent longitudinal rows of holes 5 in the cathode. The grooves are cut out in the plate so that after each pass of the tool electrode, there are produced in the blank: full holes 5 of one longitudinal row, hole-halves 5' of two rows adjoining thereto, and corresponding sections of the filaments 3 and 4 between these holes 5.

An electron tube cathode has a hollow cylindrical structure formed by thermo-emissive wires mounted between two conductive supports. The two supports are mechanically fixed to each other. To prevent the deformation of the cathode when the heating is turned on and turned off, at least one spring is used, this spring being integrated with one of the supports and being placed in the vicinity of the thermo-emissive wires. The spring is made of a material possessing elastic properties which, at ambient temperature, are lower than or equal to the properties that it has at a temperature greater than ambient temperature.