To unify the distribution of heat exchanging medium by a method wherein the heat exchanging medium is prevented from flowing into a tank or the like, arranged at deep side with respect to an inlet port unit, at a dash when the flow rate of the heat exchanging medium is big while the heat exchanging medium is prevailed to the tank or the like, arranged at the deep side with respect to the inlet port, even when the flow rate of the heat exchanging medium is small.

Tube elements, constituting blocks 28, 29, are provided with through holes 25, having a small flow passage area, at positions biased to the lower side of a tank 20 while a tube element, constituting a block 31, is provided with through holes 25, having the small flow passage area, at positions biased to the lower side of the tank. On the other hand, a tube element, constituting a block 27, is provided with the through holes 25, having the small flow passage area, at positions biased to the lower side of the tank 20 and through holes 26, having a small flow passage area, at positions above the through holes 25 while a tube element, constituting a block 30, is provided with the through holes 25, having the small flow passage area, at positions biased to the lower side of the tank and the through holes 26, having the small flow passage area, at positions above the through holes 25.