A rubber composition contains: (A) a polymer having a carbon-carbon unsaturated bond and exhibiting a value α of 0.6 or more as obtained by the following formula (i): α=(p+(0.5×r))/(p+q+(0.5×r)+s)  (i) wherein p, q, r, and s are the proportions by mole of structural units represented by the following formulae (1), (2), (3), and (4), respectively in the polymer: and (B) modified silica.