A throw-away tip of which two principal surfaces each has a land surface provided along the periphery thereof, a central surface provided on the inside of the land surface, a recess (a chip breaker groove) interposed therebetween, and at least one protrusion that extends from the central surface toward the land surface, wherein height of the land surface is made equal to the height of at least the top surface of the protrusion so that at least the top surface of the protrusion of the central surface and the land surface both serve as contact surface is provided.