Cutting insert

A cutting insert for cutting off or grooving, comprising:

• a leading cutting edge having a rake angle in the range of 20° to 35° in a central region of the cutting insert in a width direction;
• and
• a rake face having a breaker groove formed in the central region and land portions, the land portions being formed with the breaker groove therebetween in the width direction,
• wherein the land portions have a rake angle smaller than the rake angle in the central region of the cutting insert in the width direction, and
• wherein the breaker groove includes opposing side faces separated from each other by a distance that decreases with increasing distance from the leading cutting edge and four shoulder portions of the same height that are formed on the opposing side faces at positions above the land portions, two of the shoulder portions being closer to the leading cutting edge and to outer sides in the width direction than the other two shoulder portions are.