PURPOSE: To develop a high strength cylinder liner having characteristics more excellent than those of a cylinder liner made of layered graphite cast iron by producing the cylinder liner of an internal combustion engine of spheroidal graphite cast iron contg. specified amounts of B and P or V as well.

CONSTITUTION: The cylinder liner of a large internal combustion engine is made of spheroidal graphite cast iron, its compsn. is composed of the one contg., by weight, 3.2 to 3.9% C, 2.1 to 2.7% Si, 0.1 to 0.4% Mn, <0.01% S, 0.025 to 0.06% Mg and 0.5 to 1.5% Cu, contg., as alloy components, 0.01 to 0.03% B and 0.2 to 0.4% P or contg., at need, 0.1 to 0.3% V, and as for the structure of the cast iron, there is a cementite/steadite part occupying by an area of 3 to 8% uniformly distributed into the shape of an obviously limited network as well as spheroidal graphite, by which the fracture strength of the cylinder liner can be increased without deteriorating the running characteristics and wear strength of a piston ring in the surface of the cylinder liner than the case of layered graphite cast iron.