INSERT AND CUTTING TOOL

An insert may include a first surface, a second surface, a third surface located on a side opposite to the first surface, a cutting edge located on a ridgeline between the first surface and the second surface, and a convex part located more inside the first surface than the cutting edge. The first surface may include a groove extending from a first end part closest to the cutting edge to a second end part. The groove may include an opening located in the first surface, and a bottom surface. An imaginary plane which is orthogonal to a central axis and is located between the first surface and the third surface may be a reference plane, the bottom surface may include an inclined portion inclined so as to come closer to the reference plane as going toward the first end part in a breaker region.