Ebullition cooling device for heat generating component

The invention provides an ebullition cooling device for a heat generating component B which device comprises a boiling unit for boiling a refrigerant A contained therein with the heat generated by the heat generating component B as attached to an outer surface of the unit, a condensing unit disposed above the boiling unit for condensing a refrigerant vapor A flowing thereinto from the boiling unit by heat exchange with an external fluid C, and a communication pipe interconnecting the units and having a refrigerant vapor channel and a refrigerant condensate channel therein. The cooling device can be designed with greater freedom, and is therefore fully useful for electronic devices which are compacted or higher in complexity, smaller in the amount of refrigerant to be enclosed therein and outstanding in heat dissipating performance.