A ball end mill is disclosed which has an end mill body (1), an indexable cutting insert (4), a clamp screw (6) and an engaging portion (10). The end mill body (1) includes an axis of rotation therethrough and an insert receiving recess (2) formed in a forward end portion thereof. The insert receiving recess (2) has a concavely curved bearing wall. The insert (4) is generally of an elliptical shape having a pair of convexly curved side faces, and is received in the recess (2) with one of the side faces being held in engagement with the bearing wall. The clamp screw (6) releasably secures the cutting insert to the insert receiving recess. The engaging portion (10) is provided on the end mill body so as to be adjacent to the insert receiving recess (2), and is adapted to be held in engagement with the other side face of the insert. <IMAGE>
