A ball end mill comprising a ball end cutting edge (110, 120) on a distal end in an axis line (o) direction, a rotation locus of the ball end cutting edge (110,120) around the axis line (o) being formed in an approximately hemispherical shape, wherein the ball end cutting edge (110, 120) includes a plurality of large diameter edges (111a,111b,111c,111d,111e), and each large diameter edge is formed in an arc shape having a curvature radius larger than a ball radius of the ball end cutting edge (110, 120), wherein the ball radius is a length of a line segment perpendicularly extending from the axis line to an outer peripheral end (E1; E2) of the ball end cutting edge (110;120), and an intersection point between the line segment and the axis line becomes the center of the first ball end cutting edge and the second ball end cutting edge, a plurality of the large diameter edges (111a,111b,111c,111d,111e) are formed in a region 80% or more to 120% or less of the ball radius from the center of the ball end cutting edge (110,120) from a distal end to an outer peripheral end of the ball end cutting edge (110,120), the plurality of large diameter edges (111a,111b,111c,111d,111e) each have an identical cutting width in a predetermined region from the distal end to the outer peripheral end side of the ball end cutting edge (110,120), the plurality of large diameter edges (111a,111b,111c,111d,111e) each have the identical curvature radius, and when an imaginary circle having the ball radius is drawn with the center of the ball end cutting edge (110,120) as a center, the imaginary circle internally contacts respective rotation loci of the plurality of large diameter edges (111a,111b,111c,111d,111e). a ball end cutting edge (110, 120) on a distal end in an axis line (o) direction, a rotation locus of the ball end cutting edge (110,120) around the axis line (o) being formed in an approximately hemispherical shape, wherein the ball end cutting edge (110, 120) includes a plurality of large diameter edges (111a,111b,111c,111d,111e), and each large diameter edge is formed in an arc shape having a curvature radius larger than a ball radius of the ball end cutting edge (110, 120), wherein the ball radius is a length of a line segment perpendicularly extending from the axis line to an outer peripheral end (E1; E2) of the ball end cutting edge (110;120), and an intersection point between the line segment and the axis line becomes the center of the first ball end cutting edge and the second ball end cutting edge, a plurality of the large diameter edges (111a,111b,111c,111d,111e) are formed in a region 80% or more to 120% or less of the ball radius from the center of the ball end cutting edge (110,120) from a distal end to an outer peripheral end of the ball end cutting edge (110,120), the plurality of large diameter edges (111a,111b,111c,111d,111e) each have an identical cutting width in a predetermined region from the distal end to the outer peripheral end side of the ball end cutting edge (110,120), the plurality of large diameter edges (111a,111b,111c,111d,111e) each have the identical curvature radius, and when an imaginary circle having the ball radius is drawn with the center of the ball end cutting edge (110,120) as a center, the imaginary circle internally contacts respective rotation loci of the plurality of large diameter edges (111a,111b,111c,111d,111e).