A surface-coated boron nitride sintered body tool is provided, in which a cutting edge portion includes a compound sintered body and a coating layer. The compound sintered body includes cBN particles. The compound sintered body includes 45-80 vol % of cBN particles. A first particle size distribution curve of the cBN particles has one or more peaks in a range in which a particle size is 0.1-0.7 μm. A second particle size distribution curve of the cBN particles has a first peak having a maximum peak height in a range in which the particle size is 2.0-7.0 μm. An integral value ratio (Io/It×100) is 1-20, in the second particle size distribution curve, the integral value Io being in the range in which the particle size is 0.1-0.7 μm, and the integral value It being in an entire range.