PURPOSE: To averagely perform cooling, by connecting plural heat receivers and heat radiators having a hollow part sealing working liquid in the inside respectively through a pair of vapor pipes and liquid pipes and connecting one of the vapor or liquid pipes to the other heat radiator.

CONSTITUTION: When temperature of a bearing part in the side of a heat receiver 1 begins to increase higher as compared with the temperature in the side of a similar heat receiver 11, working liquid in the receiver 1 at its vaporization, generates a larger amount of vaporization, higher vapor pressure and temperature as compared with liquid in the receiver 11, and a larger amount of the latent heat of vaporization is removed by the amount of vapor becoming larger perform a higher level of cooling, thus a temperature rise in the side of the receiver 1 becoming larger than the temperature rise in the side of the receiver 11 is suppressed. Then vapor at high temperature in the receiver 1 moves to a heat radiator 21 via a vapor pipe 5 and is cooled by air in the periphery. Temperature of liquid condensed in a heat radiator 21 is higher as compared with that of liquid condensed in a heat radiator 2, and the liquid flows into the receiver 11 accordingly a temperature rise in the side of the receiver 11 is increased by the higher degree of liquid temperature, thus a difference between temperatures in the both bearing parts can be suppressed smaller.