Abstract: In order to improve cutting insert economy with simplified manufacture, an exchangeable insert (1) is configured generally symmetrical in the form of a four-cornered plate with four cutting edges (4) in the corners respectively and with plane-parallel abutment surfaces (5) disposed between the cutting edge portions and at right angles to each other. All of the cutting edge portions are mutually identical to each other, and each cutting edge portion is symmetrically formed about a bisector which passes through a circular center hole in the insert. This is provided in order to achieve a high degree of accuracy with respect to position and direction when attaching the cutting insert to the holder (3).