PURPOSE: To unify the amount of fluid, which flows through a plurality of returning flow passages, and improve the performance of a heat exchanger by a method wherein choking plates, provided with punched holes or burring holes for choking the inside flow passage area of a tank, are fixed to a part, at least at the inside of one of first and second tanks and in the part where the fluid flows into the axial direction of the tank.

CONSTITUTION: Choking plates 35, 35, choking the inside flow passage area of a second tank 22, are fixed to the inside of a part, constituting the downstream side half of the second tank 22 and the upstream side end of a third chamber 31. The configuration of the outer peripheral rim of the choking plates 35 is shaped so as to coincide with the configuration of the inner peripheral surface of the second tank 22 so that the choking plates can be fixed to the inside of the second tank 22 without any clearance. Respective choking plates 35 are provided with a punched hole 36 or a burring hole 37 at the central parts thereof whereby flow passage areas are choked at parts whereat the choking plates 35 are formed on the half way of the second tank 22.