CUBIC BORON NITRIDE SINTERED BODY AND COATED CUBIC BORON NITRIDE SINTERED BODY

This is to provide a cubic boron nitride sintered body and a coated cubic boron nitride sintered body in which tool life thereof is elongated by improving wear resistance. Provided is a cBN sintered body comprising cBN with 40% by volume or more and 85% by volume or less, a binder phase with 15% by volume or more and 60% by volume or less and inevitable impurities, wherein the binder phase comprises an Al compound comprising an Al element and at least one element selected from N, O and B, and a Zr compound comprising a Zr element and at least one element selected from C, N, O and B, the Zr compound comprises ZrO, or ZrO and ZrO 2 , and in an X-ray diffraction, when an peak intensity of a (111) plane of the ZrO was represented as I 1 , an peak intensity of a (101) plane of tetragonal ZrO 2 was represented as I 2t and an peak intensity of a (111) plane of cubic ZrO 2 was represented as I 2c , then a ratio of the intensity of I 1 based on the total intensities of I 1 , I 2t and I 2c is 0.6 or more and 1.0 or less, and an average grain size of the Al compound is 80 nm or more and 300 nm or less.