Hard-film-coated drill

A hard-film-coated drill having a drill body with a surface coated with a hard film, the drill body being made of a cemented carbide and having two or more cutting edges, a flank surface, a rake surface, and a margin,

• wherein the drill body is provided with a chamfered surface adjacent to the flank surface and the rake surface,
• a surface hardness of the hard film is within a range of 2000 to 2500 HV in Vickers hardness,
• a first ridgeline where the chamfered surface and the flank surface intersect and a second ridgeline where the flank surface and the margin intersect are formed in a round shape in cross section,
• a radius r1 (in μm) of curvature of the round shape of the first ridgeline is within a range represented by a formula r1=0.45×D+a1 (10≤a1≤25), where D is a diameter (in mm) of the drill body and a1 is a constant (in μm) to keep r1 within an upper limit and a lower limit, and
• a radius r2 (in μm) of curvature of the round shape of the second ridgeline is within a range represented by a formula r2=0.65×D+a2 (39≤a2≤67), where a2 is a constant (in μm) to keep r2 within an upper limit and a lower limit,
• wherein the hard film includes a first layer formed of a first hard film containing a nitride that includes Al and Ti, a second layer formed by alternately stacking second and third hard films having different compositions, and a third layer formed of a fourth hard film containing a nitride that includes Ti and Si, and the first to third layers are stacked in this order from a drill body side, and
• wherein the second hard film contains a nitride that includes Ti, Al and Si, and the third hard film contains a nitride that includes Ti, Al, Cr and Si.