Rubber composition which improves dispersibility of silica and enhances processability by reducing viscosity of an unvulcanized rubber and which suppresses rubber scorching, inhibits shrinkage without delaying a vulcanization rate and improves a heat resistance, and a tire prepared by using the above rubber composition. Rubber composition prepared by blending at least one rubber component selected from a natural rubber and/or a diene base synthetic rubber with silica and a glycerin fatty acid ester composition, wherein a blend amount of the glycerin fatty acid ester composition is 0.5 to 15 parts by mass based on 100 parts by mass of the rubber component; the fatty acid has 8 to 28 carbon atoms; the glycerin fatty acid ester composition contains glycerin fatty acid monoester and glycerin fatty acid diester; and a content of the glycerin fatty acid monoester in the glycerin fatty acid ester composition is 85% by mass or less.