To provide an ebullient cooling-type heat exchange device capable of sufficiently achieving high cooling performance even if a temperature difference between high-temperature air passing through a refrigerant tank and cooling air passing through an outdoor heat exchanger is large.

An indoor heat exchanger 4 absorbing air heated by a heating element 3 and heat generated from the heating element 3 has a plurality of tubes 20 vertically extending, fins 21 disposed between the tubes 20, and an upper header 22 and a lower header 23 connecting both ends of the tubes 20. The upper header 20 has a header 24 and a header expansion portion 25, and a cross-sectional area of the upper header 24 is larger than a cross-sectional area of the whole flow channel of the tubes 20. As a result, the increase of a pressure loss in evaporating a refrigerant is prevented, and the degradation of cooling performance can be prevented.