Patent ID: 8684642

Claim:
A cutting insert, comprising: an upper face; a lower face; a side face located between the upper face and the lower face; an upper cutting edge located at an intersection of the upper face and the side face; and a lower cutting edge located at an intersection of the lower face and the side face, the cutting insert further comprising: a through hole extending from the upper face to the lower face, wherein the upper face has a substantially polygonal shape, the side face comprises a first side face and a second side face adjacent to the first side face, the first side face comprises: at least one upper concave part which extends to the upper face along a thickness direction, and divides the upper cutting edge into a plurality of divided upper cutting edges; and at least one lower concave part which extends to the lower face along the thickness direction, and divides the lower cutting edge into a plurality of divided lower cutting edges, the at least one upper concave part and the at least one lower concave part are separated from each other through a thick part being continuous along a width direction of the side face, when reversed by using a reference line as an axis which passes through the intersection point of diagonals of the side face and which is perpendicular to the central axis of the cutting insert, the at least one lower concave part after the reversal overlaps with at least one of the plurality of divided upper cutting edges before the reversal in a top view, and the thick part comprises a curved region extending in the shape of a wave from one end to the other end in the width direction of the first side face in a side view.