PURPOSE: To produce an Al-Mn alloy for brazing excellent in intergranular corrosion resistance and to produce a brazing sheet using the same as a core material.

CONSTITUTION: This Al-Mn alloy for a brazing sheet has a compsn. contg. 0.5 to 3.0% Mn, 0.01 to 0.5% Bi, and the balance substantially Al. Moreover, 0.1 to 1.0% Zn is added thereto. Furthermore, one or more kinds selected from among 0.1 to 1.5% Cu, 0.05 to 0.3% Ti, 0.05 to 0.4% Cr and 0.05 to 0.4% Zr are added thereto. Also, 0.1 to 1.0% Mg is added thereto, and the content of Si is regulated to <0.2%. The grain size of Bi is regulated to 1 to 20μm, and the density thereof is regulated to 40 to 2000 pieces/mm2. Each Al-Mn alloy used as a core material and Al-Si series, Al-Si-Mg series or Al-Si-Mg-Bi series is used as a surface material of the brazing filler metal to constitute the brazing sheet.