To provide a cutting insert used for grooving with superior chip discharge performance.

This cutting insert has a rake surface formed on an upper surface, a clamp surface formed on the upper surface and clamped by a holder, a rising part slantingly formed upward for approaching the clamp surface from the rake surface, a flank formed on a side surface, and a cutting edge formed in a crossing part of the rake surface and the flank, and is constituted so as to form a projection 10 by at least one in the rising part 4.