There is provided a branched conjugated diene copolymer prepared by copolymerizing 1 to 99% by weight of a branched conjugated diene compound (1): wherein R1 is an aliphatic hydrocarbon having 6 to 11 carbon atoms, less than 99% by weight of a conjugated diene compound (2): wherein R2 and R3 are the same or different and each is a hydrogen atom, or the like, and less than 99% by weight of a vinyl compound (3): wherein R4 is an aromatic hydrocarbon group having 6 to 10 carbon atoms, or the like. The branched conjugated diene copolymer is useful as a rubber component of a rubber composition for a tire enhancing both of abrasion resistance and grip performance to a high level and exhibiting excellent processability.