PURPOSE: To obtain a high heat exchange efficiency with an improved heat transmissiveness by heating the boiling fluid at a higher temperature than the fluid.

CONSTITUTION: Boiling fluid flows in at the lower end lengthwise with respect to the heat transfer plate 15 and fluidizes through a passage formed with the heat transfer plate and a seal plate 4. In the mean time, the fluid flows into a header 11 through a high temperature fluid inlet 13 and undergoes a heat exchange with a high temperature fluid distributed into a hole provided on the heat transfer plate 15. The high temperature fluid is trapped into a header 12 and made to flow out of the equipment. With such an arrangement, the boiling fluid becomes shorter in the unboiling period, which increases the voidity within the boiling fluid passage thereby improving the heat transfer property on the boiling side and ultimately the heat exchange efficiency.