To obtain an absorption refrigerator having excellent corrosion resistance even in concentrated LiBr aqueous solution and hard corrosion even with alkali property by forming chemical formula from on an aluminum or aluminum alloy surface.

The absorption refrigerator comprises a high temperature regenerator 1, a heat exchanger 2, an absorber 3, a low temperature regenerator 4, a condenser 5, a pipe for connecting them and a pump 7 for circulating solution and refrigerant. As absorption medium, halogen metal salt such as LiBr, LiCl, or LiI is used. As the refrigerant, water is used. An Al2O3 or Al2O3.H2O film is formed on aluminum or aluminum alloy surface. Thus, excellent corrosion resistance is provided even in concentrated LiBr water solution and hard corrosion is provided even in alkali property. Since it is not necessary to set the LiBr water solution of absorbent to alkali, a working environment at the time of using, maintenance, manufacturing or discarding is improved.