A marking device for printing identification marks on the surface of an object, for example a series of billets conveyed in succession on a roll table, is mounted for vertical and pivotal movement on the end of an upper arm. The upper arm is movable along a first axis in a horizontal plane to extend and retract the marking head assembly into and out of marking position. The upper arm is supported by a carriage which is also movable in a horizontal plane parallel to the roll table along a second axis angularly positioned relative to the first axis. The upper arm is movable relative to the carriage, and the carriage is movable on a beam to carry the upper arm together with the marking device to a preselected position with respect to the objects to be marked on the roll table. The main beam for supporting the carriage is fixed to a base by a pivotal mounting for pivotal movement of the main beam about a horizontal axis by operation of a lift cylinder to move the marking device in an arcuate path into and out of marking position. Thus the marking device is movable in a plurality of directions in a horizontal plane, as well as vertically and rotationally about a vertical axis and also movable in a lifting operation through an arcuate path.