To provide a method for manufacturing a heat exchanger tube with which the heat exchanging capacity is further improved because the inner surface area of the tube can be more enlarged by enabling the increase of fin height and narrowing a fin pitch beyond the limit of a method by only extrusion.

After manufacturing the tube 1 made of aluminum on which a lot of inner fins 3 are projectively formed inward in the radial direction from the inside wall surface in cross-sectional view by extrusion, the diameter of the tube can be contracted and also the fin pitch can be reduced without substantially changing the fin height by applying the drawing work to this tube 1.