A cutting blade 5 is formed by firmly fixing a tip 4 comprising a superabrasive compact to the top end of a shank 2. Nick grooves are formed on the cutting blade as a lateral separation means for separating swarf in the lateral direction and rounding treatment is applied to the cutting edge 6 of the cutting blade in order to configure a longitudinal separation means for separating the swarf in the longitudinal direction. The swarf is separated at the part of the cutting blade in both the lateral and longitudinal directions and fractionized into very fine pieces. By doing so, it is possible to provide a drilling tool which allows swarf to be surely separated in the lateral and longitudinal directions and fractionized even when a hole is created with a large machining thickness in the radial direction.