A nodular graphite cast iron is provided, having a pearlite matrix, with high strength and high toughness. The nodular graphite cast iron consists essentially of, by weight %: from 3.0 to 4.6% of carbon; from 1.6 to 2.5% of silicon; from 0.2 to 0.6% of manganese; from 0.02 to 0.05% of magnesium; from 0.0004 to 0.090% of zirconium; at least one of tin and copper such that .alpha. ranges from 0.01 to 0.06% where .alpha. indicates a tin conversion amount defined by a summation of a weight % of the tin and 0.1.times. a weight % of the copper; and the balance of iron and inevitable foreign matters.