BALL END MILL

Provided is a ball end mill which is capable of performing both cutting and polishing well and in which cutting resistance at a tip part is low. A ball end mill formed with a plurality of chip discharge grooves 2 on an outer periphery of a tool body 1 from a tool tip toward a proximal end side, and provided with ball-nosed end cutting edges 5, 6 on a crossing ridgeline part between a rake surface 3 of the chip discharge grooves 2 and a spherical tip surface 4 of the tool body 1, said ball end mill having a tool rotation center O on the spherical tip surface 4 and a center-nearing ball-nosed end cutting edge 5 set so that a distance X from the tool rotation center O to the point closest to the tool rotation center O on one ball-nosed end cutting edge 5 in a view of the tool tip is shorter than a same distance Y to the other ball-nosed end cutting edge 6.