Abstract: The winding small tube apparatus comprises an extruded flat tubed strip having a plurality of openings leading to parallel lumens and a header for attaching to an end of this extruded flat tubed strip to cover the openings. Every other portion of the partition at the openings of the lumens disposed in the extruded flat tubed strip is cut away to connect the lumens to form a continuous winding, serpentine sealed channel. By this invention, the manufacturing process is facilitated, the overall height of the apparatus is lowered, and the heat exchange property is raised.