A drill includes a shank and a body having an outer peripheral surface with a certain outer diameter and a distal end tapered surface of a certain distal end angle. The drill includes a pilot shaft portion projecting from the distal end tapered surface of the body and having a diameter smaller than the body and having an outer peripheral surface of a certain outer diameter. The drill further includes an odd number of twisted grooves extending from the outer peripheral surface of the body to the outer peripheral surface of the pilot shaft portion at a certain twisted angle, an odd number of main cutting edges formed on the distal end tapered surface of the body by forming of the twisted grooves, and an odd number of auxiliary cutting edges formed on the distal end tapered surface of the pilot shaft portion by forming of the twisted grooves.