A method of manufacturing a diamond sintered body includes the following steps: preparing a diamond powder having a particle size within a range of 0.1 to 10 .mu.m, coating the surface of each particle of the diamond powder with a sintering assistant agent including Pd within a range of
A polycrystalline diamond cutting tool comprises a tool material of polycrystalline diamond formed by low-pressure vapor deposition, which is bonded to a shank of cemented carbide through a brazing layer. The thickness of the polycrystalline diamond layer is set at 0.1 to 1.0 mm, whi