Radius end mill having radius edge enhanced in resistance to chipping and fracture

A radius end mill having a bottom edge formed on the end face thereof, a radius edge designed in a substantially quarter arc shape and formed at a corner portion thereof, and an outer peripheral edge formed spirally on the side surface thereof, the bottom edge and the radius edge being continuously connected to each other at a connecting point A while the radius edge is continuously connected to each other at a connecting point B, and when the intersecting angle between the axial direction of said radius end mill and the normal-line direction at any position of said radius edge is represented by R, the connecting point A corresponding to the R=0° position of said radius edge while the connecting point B corresponds to the R=90° position of said radius edge, characterized in that a view taken along a plane that passes through the connecting points A and B and crosses a rake face of the radius edge is represented by an R cross-sectional view, said rake face of said radius edge is designed to have a convex curved line extending from the connecting point A to the connecting point B in the R cross-sectional view.