To provide an aluminum alloy casting for electric conductor parts, an alternating-current motor rotor casting, and production of these castings.

The Al alloy casting for electric conductor parts contains, by weight, 0.05-0.5% Si, 0.1-1.0% Fe, and 0.002-0.1% B and has ≥60% IACS electric conductivity. The Al alloy casting further contains 0.05-0.2% Zr and has ≥45% IACS electric conductivity. The casting can be produced by filling a mold with the molten Al alloy, solidifying the molten Al alloy under a pressure as high as ≥50MPa pressurizing force, and subjecting the resultant aluminum alloy casting to heat treatment consisting of holding at 400-550°C for ≥1.8×103sec. By method, the use of a low purity Al metal is made possible and casting defects can be minimized even in the case of parts with great fluctuations in wall thickness, and cast parts with high electric conductivity or cast parts excellent in high temp. strength and electric conductivity can be obtained.