Steel cord for reinforcement of rubber articles and pneumatic tire using the same

A steel cord for reinforcement of rubber articles, having a multi-twisted structure in which a plurality of strands are twisted together, said strands having a layered twisted structure in which a plurality of steel filaments are twisted together,

• wherein dc/ds, which represents the ratio between dc, the diameter of each outermost layer sheath filament constituting the outermost layer sheath of a core strand, and ds, the diameter of each outermost layer sheath filament constituting the outermost layer sheath of sheath strands, is 1.05 to 1.25,
• wherein said core strand consists of a core, a first sheath, and a second sheath, and said sheath strands consist of a core and a first sheath,
• wherein the number of said core strand is only one,
• wherein the twist angle of the sheath strand, among said strands, is not less than 1.4 rad, and
• wherein the core strand has a structure of 3+9+11 filaments.