The present invention provides a rubber composition, in which reaction efficiency of the silane coupling agent in kneading is improved, generation of bubbles is suppressed, abrasion resistance is improved and rolling resistance is reduced. Specifically, the rubber composition comprises silica and 3 to 15 parts by weight of a silane coupling agent and 1.5 to 15 parts by weight of a potassium salt based on 100 parts by weight of the silica.