Fluidity of Cu-8%Sn base ternary alloys containing Si, Al or Fe was measured with spiral shell mold. The alloys showed the minimum fluidity at a dilute concentration of Si, Al or Fe and high fluidity at higher concentration. The metal flows in two different states : complete liquid state and liquid-solid coexisting state. Flow length in the complete liquid state decreases with Si or Al content. It decreases first and then increases with increasing Fe content. When the alloy contains Si or Al, slender dendrites grow and the fraction solid at the flow stop is low at dilute concentration of Si or Al, while it increases at concentration higher than 1 percent, because of rupture of dendrites. When the alloy contains Fe, shorter and rounded dendrites grow and the fraction solid at flow stop increases remarkably. Flow length in the liquid-solid coexisting state depends on the fraction solid at flow stop. Fluidity of the alloys is represented by the sum of the lengths of the above two states.