A fluorescent luminous tube includes a plurality of cathode filaments, a multiplicity of a cathode wirings, each cathode wiring including one or more terminal portions and a wiring portion and being formed of a metal layer, and one or more intermediate portions, each being made of a metal layer. The cathode filament is grouped into at least one set of one or more filaments and filaments in each set are connected in series by fixing an end portion thereof on a terminal portion or an intermediate portion by ultrasonic wire bonding or ultrasonic bonding.