PURPOSE: To produce a hard Al alloy sheet for a can end which permits reduction in thickness by subjecting an Al alloy casting ingot contg. a specific ratio of Mg and Cu to a specific treatment and specifying the average crystal grain size prior to final cold rolling.

CONSTITUTION: An Al alloy casting ingot contg., by wt% 2.0W5.0% Mg and 0.05W0.50% Cu, contg. if necessary 0.05W0.50% Mn and 0.10W0.40% Cr and consisting of the balance substantially Al is subjected to soaking and hot rolling at 450W550°C. The hot-rolled Al alloy is then heated to 400W600°C at a heating rate of ≥100°C/min with or without cold rolling. The heated Al alloy sheet is cooled to ≤200°C at a cooling rate of ≥100°C/hr right after heating or after holding within 10min so that the average crystal grain size is made ≤25μ and that the component incorporated therein to make contribution to prevention of conversion is made into a solid soln. state. The sheet is further subjected to the cold rolling at ≥10% and the hard Al alloy sheet having an excellent bulging property, high strength and formability is obtd.