Spheroidal graphite cast-iron for engine exhaust system component

The spheroidal graphite cast-iron used for an engine exhaust system component comprises, based on the total weight thereof, carbon (C) 3.0-3.4 wt%, silicon (Si) 4.2-4.5 wt%, manganese (Mn) 0.1-0.3 wt%, sulfur (S) 0.002-0.01 wt%, phosphorous (P) 0.05 wt% or less, magnesium (Mg) 0.035-0.055 wt%, molybdenum (Mo) 0.9-1.2 wt%, nickel (Ni) 0.2-0.5 wt%, vanadium (V) 0.4-0.6 wt%, niobium (Nb) 0.1-0.4 wt%, cerium (Ce) 0.005-0.01 wt%, aluminum (Al) 0.003-0.007 wt%, and the balance iron (Fe). Therefore, the spheroidal graphite cast-iron can have a thinner surface oxide layer, and can retain improved fluidity.