A cutting insert, comprising: an upper face; a lower face; a side face which is located between the upper face and the lower face and comprises at least one upper concave portion extending along a thickness direction up to the upper face; a plurality of divided upper cutting edges (51a, 51b, 51c) which are located at an intersection of the upper face and the side face and are divided by the at least one upper concave portion, and each of the plurality of divided upper cutting edges (51a, 51b, 51c) comprises a first end (511b, 511c) located at one end and a second end (512b, 512c) located at the other end, and is inclined such that the second end (512b, 512c) is closer to the lower face than the first end (511b, 511c), when viewed from the side, characterized in that the plurality of divided upper cutting edges (51a, 51b, 51c) comprise a first divided upper cutting edge, and a second divided upper cutting edge having its first end adjacent to the second end of the first divided upper cutting edge wherein the at least one upper concave portion is between said ends of the first and the second divided upper cutting edge, when viewed from the side, the first end of the second divided upper cutting edge is located above an intersection of an extension line extending from the first divided upper cutting edge toward the second divided upper cutting edge, and a line which passes through the first end of the second divided upper cutting edge and is parallel to the central axis of the cutting insert, and when viewed from the side, the first end of the second divided upper cutting edge is located at the same height as the second end of the first divided upper cutting edge or is located lower than the second end of the first divided upper cutting edge. an upper face; a lower face; a side face which is located between the upper face and the lower face and comprises at least one upper concave portion extending along a thickness direction up to the upper face; a plurality of divided upper cutting edges (51a, 51b, 51c) which are located at an intersection of the upper face and the side face and are divided by the at least one upper concave portion, and each of the plurality of divided upper cutting edges (51a, 51b, 51c) comprises a first end (511b, 511c) located at one end and a second end (512b, 512c) located at the other end, and is inclined such that the second end (512b, 512c) is closer to the lower face than the first end (511b, 511c), when viewed from the side, characterized in that the plurality of divided upper cutting edges (51a, 51b, 51c) comprise a first divided upper cutting edge, and a second divided upper cutting edge having its first end adjacent to the second end of the first divided upper cutting edge wherein the at least one upper concave portion is between said ends of the first and the second divided upper cutting edge, when viewed from the side, the first end of the second divided upper cutting edge is located above an intersection of an extension line extending from the first divided upper cutting edge toward the second divided upper cutting edge, and a line which passes through the first end of the second divided upper cutting edge and is parallel to the central axis of the cutting insert, and when viewed from the side, the first end of the second divided upper cutting edge is located at the same height as the second end of the first divided upper cutting edge or is located lower than the second end of the first divided upper cutting edge.