This invention provides a rubber composition highly balancing flexibility at a low temperature and a low rolling resistance, which is formed by compounding a low-molecular weight conjugated diene-based polymer (B) having at least one functional group, an aromatic vinyl compound content of less than 5% by mass and a weight average molecular weight as measured without terminating by modification through a gel permeation chromatography and converted to polystyrene of not less than 2,000 but less than 150,000 and a filler (C) into a high-molecular weight rubber component (A) having a weight average molecular weight as measured without terminating by modification through a gel permeation chromatography and converted to polystyrene of not less than 150,000.