PURPOSE: To obtain a panel-shaped heat exchnger blank material used for a water heater utilizing solar heat, a space-heating radiator or the like and a method of manufacturing the same, by using a copper material in making a fluid passage constituting member and an aluminum material in making other part of a heat exchanger including fins, and bonding them together under pressure.

CONSTITUTION: A fluid passage constituting pipe 7 made of a copper material is held between fin portions 8 made of an aluminum material. The pipe 7 is rolled flat under low temperature by the same rolling reduction rate as the fin portions 8 and then expanded, while the fin 8 is formed with a stepped portion 9. In manufacturing a heat exchanger plate, blanks are drawn out respectively from a copper tube coil 11 having a copper tube 2' wound therearound and an aluminum sheet coil 12 having an aluminum plate 3 wound therearound and they are bonded together at uniform intervals by means of cold pressure bonding rolls 16. Then, the bonded blanks are wound around a wind-up coil 13. Prior to bonding the blanks together, the upper surface of the aluminum plate 1, the outer surface of the copper tube 2' and the lower surface of the aluminum plate 3 are made rough by means of brushes 14 at the portions thereof where they are bonded together, and at the same time, oxide layer or the like on the surface of the blanks is removed. Further, a separating medium is beforehand coated over the inner surface of the copper pipe 2' so as to prevent bonding of the inner surface of the pipe 2'. The pressure bonded plate 18 is wound up by one pass by means of the rolls 16 by making the rolling reduction rate of the aluminum plates 1, 3 and the flat copper tube 2 uniform.