A surface-coated boron nitride sintered body tool, in which at least a cutting edge portion includes a compound sintered body and a coating layer provided on a surface of said compound sintered body, said compound sintered body including cubic boron nitride particles and binder particles, said compound sintered body including 45 vol% or more and 80 vol% or less of said cubic boron nitride particles, in a case where a particle size distribution of said cubic boron nitride particles in at least one cross section of said compound sintered body is shown by a first particle size distribution curve plotted by a horizontal axis that is divided in each prescribed particle size range and a vertical axis that shows a proportion of the number of particles in each said particle size range, said first particle size distribution curve having one or more peaks in a range in which a particle size is 0.1 μm or more and 0.7 μm or less, in a case where the particle size distribution of said cubic boron nitride particles in at least one cross section of said compound sintered body is shown by a second particle size distribution curve plotted by a horizontal axis that is divided in each prescribed particle size range and a vertical axis that shows a proportion of an area occupied by particles in each said particle size range, said second particle size distribution curve having a first peak having a maximum peak height in a range in which the particle size is 2.0 μm or more and 7.0 μm or less, an integral value ratio (I o /I t × 100) between an integral value I o and an integral value I t being 1 or more and 20 or less, in said second particle size distribution curve, said integral value I o being in the range in which the particle size is 0.1 μm or more and 0.7 μm or less, and said integral value I t being in an entire range, said coating layer including an A layer that is in contact with the surface of said compound sintered body, and a B layer provided on said A layer, said A layer being made of Al l-s Cr s N (0.2 ≤ s ≤ 0.9), said B layer being made of Ti l-t Al t N (0.3 ≤ t ≤ 0.8), said A layer having a thickness of 0,05 μm or more and 0.5 μm or less, said B layer having a thickness of 0.2 μm or more and 5 μm or less, and said coating layer having an entire thickness of 0.3 μm or more and 7 μm or less. said compound sintered body including cubic boron nitride particles and binder particles, said compound sintered body including 45 vol% or more and 80 vol% or less of said cubic boron nitride particles, in a case where a particle size distribution of said cubic boron nitride particles in at least one cross section of said compound sintered body is shown by a first particle size distribution curve plotted by a horizontal axis that is divided in each prescribed particle size range and a vertical axis that shows a proportion of the number of particles in each said particle size range, said first particle size distribution curve having one or more peaks in a range in which a particle size is 0.1 μm or more and 0.7 μm or less, in a case where the particle size distribution of said cubic boron nitride particles in at least one cross section of said compound sintered body is shown by a second particle size distribution curve plotted by a horizontal axis that is divided in each prescribed particle size range and a vertical axis that shows a proportion of an area occupied by particles in each said particle size range, said second particle size distribution curve having a first peak having a maximum peak height in a range in which the particle size is 2.0 μm or more and 7.0 μm or less, an integral value ratio (I o /I t × 100) between an integral value I o and an integral value I t being 1 or more and 20 or less, in said second particle size distribution curve, said integral value I o being in the range in which the particle size is 0.1 μm or more and 0.7 μm or less, and said integral value I t being in an entire range, said coating layer including an A layer that is in contact with the surface of said compound sintered body, and a B layer provided on said A layer, said A layer being made of Al l-s Cr s N (0.2 ≤ s ≤ 0.9), said B layer being made of Ti l-t Al t N (0.3 ≤ t ≤ 0.8), said A layer having a thickness of 0,05 μm or more and 0.5 μm or less, said B layer having a thickness of 0.2 μm or more and 5 μm or less, and said coating layer having an entire thickness of 0.3 μm or more and 7 μm or less.