PURPOSE: To eliminate a galling accident of a molten metal at a low cost and to permit easy remelting by using a dummy insert metal formed of aluminum having the same shape in trial shot of aluminum die casting using the insert metal.

CONSTITUTION: A dummy insert metal formed of aluminum having the same shape is used in the first trial shot in aluminum die casting using the insert metal. The dummy metal is inexpensive and if such metal is mounted, the galling of the molten metal to dies owing to the inflow of the molten metal into the mounting part is thoroughly eliminated. The labor for separating the insert metal in the stage of remelting in trial shot production is thus eliminated and working efficiency is improved.