Cutting insert and method of manufacturing the same

A cutting insert including a surface involved in cutting, for which a cutting tool material composed of one of cBN based sintered body, ceramics, and cermet is used, the cutting insert comprising:

• a flank face;
• a nose R portion;
• a rake face having a positive rake angle;
• and a negative land with unequal width disposed between the rake face and the flank face, wherein a radius of the nose R portion is 0.4 mm or greater and 2.4 mm or less, an apex angle α of the nose R portion is 30° or greater and 95° or less,
• a rake angle β at a position of a bisecting plane of the apex angle of the nose R portion is 1° or greater and 10° or less,
• a ridge line where the negative land with unequal width and the rake face intersect, and a ridge line where the negative land with unequal width and the flank face intersect are not parallel in plan view, and at least on one side of the negative land with respect to a boundary which is an apex of a nose R portion cutting edge, a width of the negative land with unequal width gradually decreases from the apex of the nose R portion cutting edge to a position at which the nose R portion cutting edge is connected to a linear cutting edge, and let W1 be the width of the negative land with unequal width in plan view at the apex of the nose R portion cutting edge, and W2 be the width of the negative land with unequal width in plan view at the position at which the nose R portion cutting edge is connected to the linear cutting edge, then the W1 is 0.04 mm or greater and 0.2 mm or less, and a ratio of the W1 to the W2 is 1.5 or greater, and
• the ridge line where the negative land and the rake face intersect has a curved line and connects to the linear cutting edge.