A cutting insert having excellent chip discharge performance is provided. In the cutting insert of the present invention, a bottom surface of a concave groove 21 includes a first bottom surface 211 continuous with a cutting edge part 5, and a second bottom surface 212 which is located on a side further remote from the cutting edge part 5 than the first bottom surface 211, and is located at a lower position than a virtual extension line L1 of an end portion of the first bottom surface 211 on a side remote from the cutting edge part 5. Further, a pair of inclined surfaces 23 are located on a side further remote from the cutting edge part 5 than the end portion of the first bottom surface 211 on the side remote from the cutting edge part 5 in a top view. Therefore, the diameter of generated chips decreases by the fact that the chips are curled while sinking in space formed at a lower position than the virtual extension line L1 of the first bottom surface 211. Consequently, the chip discharge direction is stabilized, thus achieving satisfactory chip discharge performance.