A method and equipment for making a needle-fin tube having needle-like external fin parts, and internal fin structure formed by a spiraled spring wire which expands to clamp again the tube in the needle-fin tubes. The wire used to form the internal fin is wound along and around a bar which is moved and rotated along a straight line. The bar is moved inside the needle-fin tube from its one end to the other and the wire is released from the bar to attach to the internal surface of the needle-fin tube under spring force.