An aluminum alloy heat exchanger includes a core material formed of an aluminum alloy comprising Mn of 0.60 to 2.00 mass % and Cu of 1.00 mass % or less, with the balance being Al and inevitable impurities, and a sacrificial anode material formed of an aluminum alloy comprising Zn of 2.50 to 10.00 mass %, with the balance being Al and inevitable impurities. Pitting potential of a sacrificial anode material surface of a tube of the aluminum alloy heat exchanger in a 5% NaCl solution is −800 (mV vs Ag/AgCl) or less, and pitting potential of an aluminum fin of the aluminum alloy heat exchanger in a 5% NaCl solution is less than the pitting potential of the sacrificial anode material surface of the tube of the aluminum alloy heat exchanger in a 5% NaCl solution.