A blade section (20) has two lands (30) and two flutes (21) in an alternating manner and also has a linear chisel edge (24). The lands are each provided with: a margin section (32) that is continuous with a cutting blade; a clearance section (33) that is continuous with the margin section and that has a smaller diameter than the margin section; and a pad (34) that is continuous with the clearance section and that has the same width as the width of the margin section.
