The invention relates to a rubber composition having a good processability, and simultaneously having a rolling resistance performance and hardness after vulcanization at high levels, with which the contamination of the mold for processing due to the bleeding-out of the plasticizer can be suppressed, and in which the migration of the plasticizer and so on is suppressed to a low level; a vulcanized rubber obtained by vulcanizing the rubber composition; and to a tire including the rubber composition as at least a part thereof. The rubber composition contains 100 parts by mass of rubber component (A) composed of at least one of a synthetic rubber and a natural rubber, 0.1 to 50 parts by mass of a diene polymer (B), 20 to 150 parts by mass of a filler (C), 0.1 to 10 parts by mass of a vulcanizing agent (D), 0.1 to 15 parts by mass of a vulcanization accelerator (E) and 0.1 to 15 parts by mass of vulcanization aid (F).