In a medical or dental-medical handpiece having a tool, a drive mechanism for the tool has at least one rotary part mounted rotatably by means of a bearing arrangement. The bearing arrangement includes at least one ball bearing with a plurality of balls arranged between an inner track and an outer track, wherein the inner track of the ball bearing is formed by means of the end face of a first bearing part rotatable with the rotary part, and the outer track is formed by means of the end face of a second bearing part fixed in relation to the rotary part.