The hexagonal shank drill bit is composed of a drill bit and a drill shank. The tail of the drill bit is sleeved in the inner hole of the drill shank. A longitudinal straight rack is evenly arranged on the outer cylindrical surface of the tail of the drill bit. The tooth tip of the straight rack has a slightly radial height. Larger than the inner hole radius of the drill shank, the tooth tip of the straight rack is embedded in the base of the drill shank.