Polycrystalline cubic boron nitride

The present invention relates to a polycrystalline cubic boron nitride and, more specifically, to a polycrystalline cubic boron nitride with improved fracture resistance and abrasion resistance. According to the present invention, the polycrystalline cubic boron nitride is prepared by using CBN particles with different particle sizes, thereby simultaneously satisfying the improvement in dispersibility of a first group of CBN particles and a second group of CBN particles and the enhancement in binding strength between a binder and the cubic boron nitride while increasing binding strength between the second group CBN particles and the binder through thermal treatment, thus effectively improving abrasion resistance and fracture resistance. In addition, according to the present invention, the polycrystalline cubic boron nitride is prepared by limiting the volume ratio between the fed CBN particles, so that a tool having excellent lifespan can be manufactured through the improvement in fracture resistance and abrasion resistance.