PURPOSE: To improve the working precision for a hard brittle object by installing an outer peripheral cutter in a spiral form at an outer peripheral part and installing an edge surface cutter extending in a radial direction at the edge surface and setting the rake angle in the radial direction of the outer peripheral cutter to a specific negative angle, as for the edge part for a shank.

CONSTITUTION: An end mill 1 formed from the sintered material of a powder vice has a cutter part 3 formed integrally at the lower edge part of a cylindrical shank 2, and the outside diameter D1 of the cutter part 3 is made smaller than the outside diameter D2 of the shank 2, and an outer peripheral cutter 4 having a spiral form is formed on the outer peripheral part, and an edge surface cutter 5 extending in the radial direction is formed at the edge surface. In this case, the rake angle in the radial direction of the rake surface of the outer peripheral cutter 4 is made negative, and the negative angle is increased gradually towards the basic part along the axis line direction from the top edge side of the cutter part 3. In other words, the negative angle on the top edge side is set to about 20°, and the negative angle on the basic part side is set to about 35° Accordingly, the rigidity of the cutter part 3 is increased, and the vibration and resonance in cutting are suppressed, and the working of hard a brittle article is facilitated.