A ball end mill according to the present invention includes an end mill body (2) which is formed in a shaft shape, a plurality of convex arcuate end cutting edges (9) which are disposed on a tip portion of the end mill body (2) at intervals around an axis (O) and form a hemispherical shape such that a rotational locus around the axis has a center on the axis (O), and a plurality of gashes (7) which are respectively disposed to be adjacent to the plurality of end cutting edges (9) in an end mill rotation direction around the axis (O). The plurality of end cutting edges (9) includes a first end cutting edge of which the cutting edge length toward an inside in a radial direction orthogonal to the axis (O) is longest among the plurality of end cutting edges (9), a second end cutting edge which is adjacent to the first end cutting edge in the end mill rotation direction and of which the cutting edge length toward the inside in the radial direction is shorter than that of the first end cutting edge, and a third end cutting edge which is adjacent to the second end cutting edge in the end mill rotation direction and of which the cutting edge length toward the inside in the radial direction is shorter than that of the second end cutting edge. The depth of a gash (7B) of the second end cutting edge is deeper than that of a gash of the third end cutting edge (7C), and a depth of a gash (7A) of the first end cutting edge is deeper than that of the gash (7B) of the second end cutting edge.