A heat exchanger comprising a tube, a fin, and a header pipe, wherein the tube contains, in mass %, 0.15 to 0.45% of Mn, 0.20 to 0.50% of Si, and the balance of A1 and unavoidable impurities, and is coated with a coating of brazing composition containing 1.0 to 5.0g / m 2 of Si powder, 4.0 to 10.0 g / m 2 of KZnF 3 , and 0.5 to 3.0 g / m 2 of binder; the fin contains, in mass %, 1.20 to 1.80% of Zn, 0.70 to 1.20% of Si, 0.30 to 0.80% of Fe, 0.90 to 1.50% of Mn, one or two or more selected from 0.05 to 0.20% of Zr, 0.01 to 0.10% of V, and 0,01 to 0.10% of Cr, and the balance of Al and unavoidable impurities; and the header pipe comprises a core material, outer sacrificial corrosion protection material, and an inner brazing material.