A circular-shank tool including a shank held in a bore of a tool holder by a locking sleeve, the shank being rotatably held in the locking sleeve. The locking sleeve has one or more retaining elements that project inwards and engage in a peripheral groove in the shank of the tool, thus indisplaceably securing the locking sleeve in an axial direction on the shank of the tool. Because the locking sleeve is mirror-symmetrical to the central transversal plane, the locking sleeve can be fixed to the shank in a position that is rotated through 180°.