PURPOSE: To prevent the occurrence of stretcher strain marks at the time of forming by hot-rolling an ingot of an Al-Mg alloy with a specific composition under specific conditions and further rolling the above while exerting process- annealing between the rolling stages.

CONSTITUTION: An ingot of an Al-Mg alloy which has a composition consisting of 0.5 to 2.2% Mg as an essential component, one or more kinds among ≤0.6% Cu, ≤0.8% Mn, ≤0.3% Cr, and ≤0.2% Zr, and the balance Al with impurities is hot-rolled, which is subjected to intermediate rolling at ≥40% draft, to process annealing at 300-500°C, and further to finish rolling at ≥40% draft. If necessary, stabilizing annealing is further applied to the above at 150 to 250°C. By using this Al-Mg alloy, the occurrence of stretcher strain marks can be prevented even if deep drawing is performed, in particular, at a drawing ratio close to about 2.0 at the time of forming.