To obtain a heat pipe in which such a defect in a conventional art is eliminated that a heating medium solution having finished a heat exchange is condensed to come down the internal wall of the heat pipe, and that the liquid is heated again to evaporate it, and that a considerably long time is required for heat exchanging.

In this heat pipe 1, the condensate produced after heat exchange on the upper part by evaporation of a heating medium solution in the heat pipe is allowed to drip from protrusions 3 and collided against a crushing stand 5 for removing heat inside the pipe as heat of evaporation, and promptly evaporated. Thus the time for the evaporation cycle of the heating medium solution is reduced, and the efficiency of heat collection and exchange can be improved.