PURPOSE: To obtain an Al alloy material for heat exchanger excellent in strength and pitting corrosion resistance by providing an Al coating layer to a core material composed of an alloy having a specific composition consisting of Cu, Mn, Mg, and Al and forming a specific copper diffused layer.

CONSTITUTION: An alloy having a composition consisting of, by weight, 0.2-1.0% Cu, further 0.6-1.4% Mn and/or 0.1-0.8% Mg, and the balance Al with inevitable impurities is used as a core material. One side or both sides of this core material are clad with coating layer consisting of pure Al or Al alloy and, in the course of its manufacture or brazing heating, Cu in the core material is allowed to diffuse in the coating layer, by which a copper diffused layer having sacrificial anode effect is formed in the surface layer part. At this time, the thickness of the diffusion layer, where Cu concentration is gradually reduced from the inner part of the coating material toward the surface, is regulated to 40-300μm, and the difference in Cu concentration between the inner part and the surface is regulated to 0.15-0.6%. By this method, the sacrificial anode effect of the surface layer part of the material can be made sufficient and maintained over a long period.