END MILL

This end mill comprises three types of cutting edge, a curved tooth BS, a left hand helical tooth BL, and a right hand helical tooth BR, as three peripheral cutting edges, adjacent peripheral cutting edges being constituted from different types of cutting edge. Therefore, the spacing between adjacent peripheral cutting edges is irregular and continuously changes in the axial direction, and the direction of cutting force varies. Consequently, resonance is suppressed, and an anti-vibration effect is adequately attained. Moreover, providing the curved tooth BS results in the more adequate suppression of the occurrence of burrs in comparison to when only the right hand helical tooth BR and the left hand helical tooth BL are present, and chatter vibration in the plate thickness direction of a workpiece is reduced as the cutting force acts inward on a curved shape. Furthermore, since the curved tooth BS has a smooth curved shape, the accumulation of chips is reduced, and restrictions on processing conditions are relaxed in comparison to a herringbone shape.