PURPOSE: To prevent the degradation in a flux effect at the time of brazing by specifying the magnesium content of an aluminum alloy material and brazing the material by high-frequency induction heat using a fluoride flux.

CONSTITUTION: The content of the magnesium in the aluminum alloy material is limited to ≥0.5wt.% and ≤2.0%. The fluoride flux is used as the flux and the alloy material is brazed by the high-frequency induction heating. The brazing is executed by a preplaced filler metal system. The heating time is preferably ≤120 seconds. The shorter heating time at the time of the brazing is necessitated and the reaction of the magnesium and the fluoride flux is suppressed, by which the degradation in the flux effect is prevented.