A cubic boron nitride sintered body with excellent wear resistance and fracture resistance. The cubic boron nitride sintered body includes 85 to 95% by volume of cubic boron nitride, and 5 to 15% by volume of a binder phase and inevitable impurities. The binder phase has at least three compounds selected from carbides, nitrides, carbonitrides, oxides and mutual solid solutions thereof of Al, V, Cr, Mn, Co, Ni, Nb and Mo. An amount of an aluminum element contained in the cubic boron nitride sintered body is 0.5 to 5% by mass based on a total mass of the cubic boron nitride sintered body. The binder phase is essentially free of both pure metals and alloys consisting of pure metals.