A drill includes a blade portion provided with spiral cutting blades along a cutting direction from a tip end to a rear end, and a shank portion formed consecutively on a rear side of the blade portion. The blade portion includes distal-side cutting blades provided from the distal end of the blade portion along the cutting direction and angled at a constant first torsion angle, intermediate grooves formed at a variable torsion angle that varies gradually from the first torsion angle to a second torsion angle, and rear-side grooves formed at the constant second torsion angle. The rear-side grooves are longer than the distal-side cutting blades in the cutting direction, and the second torsion angle is greater than the first torsion angle.