A structure of a heat pipe applicable to a heat transportation device is disclosed in which an elongate metallic capillary tube is formed having an inner diaeter sufficiently small to enable movement of a bi-phase compressible working fluid having a predetrmined quantity and sealed into the metallic capillary container in a filled and closed state, a plurality of heat receiving portions and heat radiating portions being on predetermined parts of the elongate metallic tube and alternatingly arranged thereat. Both terminals of the metallic elongate capillary tube are heretically sealed thereat or hermetically connected to form a loop-type flow passage of the bi-phase compressible working fluid. In addition, no flow direction limiting mechanism such as check valves is essentially eliminated.
