Patent attributes
An end mill including a shank having one end gripped by a chuck which is rotatable about a predetermined rotation axis, and a blade body attached to the other end of the shank and rotatable together with the shank. The blade body has a shape in which the area of a cross section in a plane perpendicular to the rotation axis decreases as the distance from the shank increases, and includes a linear cutting edge parallel to, and at a certain distance from, the rotation axis. An end cutting edge adjoining the cutting edge in the longitudinal direction thereof may be provided. The blade body includes, for example, a rake-face-side surface including a rake face and adjoining the flank-side surface in two portions, and a linear cutting edge formed at one of the positions at which the flank-side surface and the rake-face-side surface come in contact with each other.