A cubic boron nitride sintered body according to the present invention is provided with 40-85 vol%, inclusive, of cubic boron nitride particles and a bonded phase. The bonded phase includes one or more first compounds comprising at least one element selected from the group comprising titanium, zirconium, hafnium, vanadium, niobium, tantalum, chrome, molybdenum, and tungsten and at least one element selected from the group comprising nitrogen, carbon, boron, and oxygen, and at least one selected from the group comprising solid solutions derived from the first compound, or, at least one selected from the group consisting of one or more first compounds and a solid solution derived from the first compound, and an aluminum compound. The cubic boron nitride particles, in terms of the numbers thereof, include 50% or more of cubic boron nitride particles having an equivalent circle diameter greater than 0.5 µm and 50% or less of cubic boron nitride particles having an equivalent circle diameter greater than 2 µm. If the mass of the cubic boron nitride particles is 100 mass%, the total content of lithium, magnesium, calcium, strontium, beryllium, and barium in the cubic boron nitride particles is less than 0.001 mass%.