PURPOSE: To improve the heat transfer efficiency making the pulsation of the heat transferring small by a method wherein the heat transfer device is composed so as the working fluid refluxes to the heat receiving part alternately from two accumulators.

CONSTITUTION: Lower part spaces of two accumulators 21, 22 are interconnected to the entrance part of a heat receiving part 1 through the intermediary of each conduit pipe 23, 24. Upper part spaces of two accumulators 21, 22 are also interconnected to the exit part of the heat receiving part 1 through the intermedary of each conduit pipe 29, 30. Furthermore, one upper space of the accumulator 21 is interconnected to the circuration entrance of the heat releasing part 2 through the intermediary of a conduit pipe 32 and the other upper space of the accumulator 22 is interconnected to the circulation exit of the heat releasing part 2 through the intermediary of conduit pipe 32. The heat transfer is carried out continuously from the heat receiving part to the heat releasing part by making the transfer of fluid between the first accumulator 21 and the second accumulator 22 by the shift of the first and second ON-OFF valves and the pulsation of the heat transfer is made small and the heat transfer efficiency can be improved.