PURPOSE: To provide a heat radiation pipe and a method of fabrication thereof, the heat radiation pipe being used for a natural convection type heat exchanger, the heat radiation pipe further having a satisfactory heat exchange efficiency and being strong and permitting a longitudinal external heat transfer fin to be formed even with metals not suited to protrusion molding other than an aluminum alloy.

CONSTITUTION: A heat radiation pipe is divided radially into several parts. Each divided longitudinal member 1 includes heat radiation pieces 11 protruded radially and integrally therewith on opposite side ends of a pipewall 9 serving as a primary heat transfer surface. The heat radiation pieces 11 are both fixedly mounted to an adjacent longitudinal member 1. Hereby, the adjacent heat radiation pieces 11 are coupled. With this coupling, an external heat transfer fin 4 is formed by collecting and joining those heat radiation pieces around the primary heat transfer pipe 2.