An Al—Si—Mg—Bi-based brazing material containing Si: 6.0% to 14.0%, Fe: 0.05% to 0.3%, Mg: 0.02% to 1.5%, Bi: 0.05% to 0.25%, Sr: 0.0001% to 0.1%, and a balance of Al and inevitable impurities, and satisfies (Bi+Mg)×Sr≤0.1, is disposed on both surfaces of a core material, Mg—Bi-based compounds of the brazing material with a diameter of 0.1 μm or more and less than 5.0 μm in terms of equivalent circle diameter are more than 20 in number in 10,000 μm2 and the Mg—Bi-based compounds with diameter of 5.0 μm or more are less than 2 in number in 10,000 μm2, the core material contains Mn: 0.8% to 1.8%, Si: 0.01% to 1.0%, Fe: 0.1% to 0.5%, and a balance of Al and inevitable impurities, and a cathode current density of a brazing material layer after a brazing heat treatment is 0.1 mA/cm2 or less.