Provided is a ball end mill that does not interfere with the defect resistance of a cutting edge of which a rotational track forms a convex hemispherical shape. In the ball end mill, a gash 4 is formed at a front end portion of a main end mill body 1 rotated about an axis O and a cutting edge 5 of which a rotational track around the axis 0 forms a convex hemispherical shape having a center C on the axis O is formed at a peripheral edge portion of a wall surface 4A of the gash 4 facing an end mill rotation direction T. A difference between an included angle, which is formed between a straight line connecting a position which is present on the cutting edge 5 and at which a depth of the gash 4 is maximal in a cross-section orthogonal to the cutting edge 5 with the center C and the axis O, and an included angle, which is formed between a straight line connecting a position which is present on the cutting edge 5 and at which a rake angle of the cutting edge 5 is maximal on a positive angle side in the cross-section orthogonal to the cutting edge 5 with the center C and the axis O, is within ±7°.