To sufficiently increase the rigidity and fatigue strength, by specifying the amount of graphite (the area ratio of graphite) and also specifying graphite shape (spheroidizing rate, grain size).

This spheroidal graphite cast iron has a composition consisting of, by weight, 1.5-3.3% C, 1.5-2.5% Si, 0.25-1.00% Mn, ≤0.05% P, ≤0.1% S, 0.02-0.07% Mg, 0.1-1.0% Cu, 0.01-0.10% Ca, 0.01-0.10% of ≥ one kind among and Sb, and the balance Fe with inevitable impurities and also has a structure in which graphite spheroidizing rate, average graphite grain size, graphite area ratio, pearlite area ratio, and ferrite area ratio are regulated to ≥86%, ≥30μm, 3-13%, 80-97%, and ≤10%, respectively. Because of reduced graphite grain size and improved graphite spheroidizing rate, Young's modulus is improved and rigidity and fatigue strength can be sufficiently increased.