PURPOSE: To improve the corrosion resistance of the titled alloy by incorporating specific ratios of Sb and Ti into a Zn-Cu-Al-Mg alloy having specific composition.

CONSTITUTION: The composition of the die casting alloy used for a wristwatch case consists of, by weight, 0.2W1.0% Cu, 10W15% Al, 0.2W1.0% Sb, 0.08W0.2% Mg, 0.2W1.0% Ti and the balance Zn. The high hardness and transferability of said alloy are improved at the time of alloying the element Sb to be added with other elements. Ti also has the effect of controlling a creep caused by the lapse of time. Since the die casting Zn alloy having said composition has the excellent corrosion resistance, the plating thickness of a wristwatch case can be reduced. The wristwatch case which retains a sharp shape and has an added value can be thus obtd.