An aluminum alloy brazing sheet used for brazing of an aluminum material in an inert gas atmosphere or in vacuum is formed of a two-layer material in which a brazing material and a core material are stacked in this order. The core material is formed of an aluminum alloy and has a grain size of 20 to 300 μm, and the aluminum alloy contains Mn of 0.50 to 2.00 mass %, Mg of 0.40 to 2.00 mass %, Si of 1.50 mass % or less, and Fe of 1.00 mass % or less, with the balance being aluminum and inevitable impurities. The brazing material is formed of an aluminum alloy containing Si of 4.00 to 13.00 mass % with the balance being aluminum and inevitable impurities, and, in a drop-type fluidity test, a ratio α (α=Ka/Kb) of a fluid coefficient Ka is 0.50 or more.