HEAT EXCHANGER

PURPOSE:To increase a heat transmitting rate and reduce the weight of the heat exchanger by a constitution wherein a corrugated inner fin is inserted into and connected to the flat hole in a flat tube having heat exchanging medium paths for the heat exchanger. CONSTITUTION:The flat tube 7 is integrated continuously from an aluminum sheet with a flat hole larger than the same in a conventional tube while the inner fin 8 is formed by pressing the aluminum sheet member into a wavy member. The inner fin 8 is inserted into the flat hole of the tube 7 and the tube 7 is pressed into the direction of the thickness of the tube 7. An aluminum brazing agent, having a melting point lower than the same of the inner fin itself, is coated on both surfaces of the inner fin 8 prior to assembling. Next, the tube 7 is bent into a meandering configuration and the whole of both members are heated to braze the tube 7 integrally with the fin 8.