An object of the invention is to reliably control
chip, particularly that produced in profiling. To achieve this, rake faces are formed on polygon faces of an insert in the form of a polygonal plate shape, and a pair of
cutting edges extending respectively from corner parts of the polygon faces are formed on a
ridge part of the polygon faces, and each of the rake faces is gradually inclined as it becomes farther away from the
cutting edge, and a land formed along the
cutting edge, is inclined so that it gradually sinks as it become farther away from the cutting edge at an
angle of inclination smaller than a
rake angle, and angles of inclination of these rake face and land are made smaller in the direction to separate from a tip of the corner part along the cutting edge, and a main convex being a convex spherical
face shape is formed at intervals between the cutting edges, on the corner part C, and at least one pair of sub convexes being a convex spherical
face shape is also formed respectively at positions away from this main convex, along the pair of cutting edges.