Abstract: A method for fabricating a direct-heated cathode structure comprising a bending process wherein the bending is carried out by a plurality of hollow punches, those are assembled around a center shaft with each cushion springs of different elastic moduli inside the hollows thereof and press a filament material with time intervals between each punches thus making the filament material corrugate-ended; and a welding process wherein an end of corrugate-ended filament is put on an upper end of bended lead bar, then electrodes of an electric resistance welder are put on the filament end and beneath said lead bar end respectively to carry out the welding. Also, an apparatus which is suitable to carry out the method comprising a corrugate bender assembly and a welding jig assembly so being prepared to perform said bending process and said welding process respectively.