cBN sintered body includes cBN and a binder phase, wherein a content of the cBN is 82-98 volume %, and in a cross section of the cBN sintered body, an isolated binder phase having an area of 0.05-0.5 μm2 has a protrusion of two or more steps, and assuming that in a first-step protrusion, A1 represents a side length which is perpendicular in a tip direction, and B1 represents a side length which is parallel in the tip direction; and in a second-step protrusion, A2 represents a side length which is perpendicular in the tip direction, and B2 represents a side length which is parallel in the tip direction, an area ratio of an isolated binder phase having a protrusion in which A1/B1 is 1-10 times of A2/B2, to the whole of the binder phase having the area of 0.05-0.5 μm2, is 25% or more.