The present invention provides a rubber composition for coating a steel cord, use of which makes it possible to consider an effect on environment, prepare for the future decrease in supply of petroleum resources, suppress generation of air bubbles, reduce rolling resistance, and improve processability, roll workability, adhesion to a steel cord and durability with favorable balance, as compared with a rubber composition for coating a steel cord comprising raw materials derived from petroleum resources as main components, and provides a tire having a belt prepared by using the rubber composition. The rubber composition for coating a steel cord comprises 40 to 80 parts by weight of silica having a nitrogen adsorbing-specific surface area of 100 to 200 m.sup.2/g, 1 to 15 parts by weight of a silane coupling agent and 0.5 to 3 parts by weight of potassium borate, on the basis of 100 parts by weight of a diene rubber component, and the tire is prepared using the rubber composition.