Provided is a drill, in which occurrence of non-uniform flank wear and/or of chipping at the cutting edge is prevented on the outer periphery side, and interruption of flank is also prevented on the inner periphery side.
In the drill,
a drill body 1 is rotatable on an axis O;
chip evacuating flutes 4, which are open on front flanks 3 of the drill body 1 and are extended rearwards, are formed in a periphery of the drill body on its front side;
cutting edges 6 are formed along ridge lines where the front flanks 3 intersect with wall surfaces of the chip evacuating flutes 4 facing a drill rotating direction T;
at least first and second front flanks 3A and 3B are formed on the front flanks 3 in order of their locations in the drill rotating direction T from its leading side to its trailing side;
a clearance angle of the second front flank 3B is greater than that of the first front flank 3A; and
intersection lines L of the first and second front flanks 3A and 3B, cross the cutting edges 6.