To provide a heat pipe allowing the working fluid to constantly exist in a heat absorbing part under an environment of minimal gravity or in a horizontal attitude under a weighted state.

This heat pipe has the heat absorbing part oppositely to a heating element mounted near a part of one tubular body, and an exhaust heat part separated from the heating element in at least one tubular body composed of a narrow pipe, and the working fluid is sealed in the heat absorbing part pipe to be fluidized, evaporated or refluxed.