Multi-blade ball end mill

Provided is a multi-blade ball end mill comprising a shank, a cutting blade section having a ball on the tip thereof, and at least three cutting blades formed in the cutting blade section. Each cutting blade comprises a peripheral blade having an angle of torsion eta of 35 to 45degrees, and a ball blade in which the angle of torsion mu at the outermost peripheral point with respect to the angle of torsion eta satisfies the relationship eta-mu smaller than 7degrees so that the ball blade is smoothly connected with the peripheral blade. The radial rake angle of the ball blade is -37 to -11 degrees, and the radial rake angle of the peripheral blade is 2 to 8 degrees. A concave sloped blade is integrally formed, near the rotational center point of the ball tip, from the tip of each ball blade to the rotational center point.