Apparatus for efficiently producing a wire fin tube for heat transfer which comprises fin-forming means for shaping a plurality of wires to a wavy shape, said fin-forming means including a pair of gears; means for guiding the wavy wires in an upstanding state including guide plates spaced apart a selected distance; means for feeding a revolving tube in a crossing direction, to the wavy wires so that the wires can be wound on the tube; means for controlling the operative speed relation of the fin forming means and the tube feeding means so that the wavy wires may be helically wound on the tube under a moderate tension so as to maintain the upstanding state and the same pitch as the distance of the guiding means; and means for welding the wire fins to the tube.