Abstract: A terminal head for processing a workpiece using a laser beam includes a housing into which an insert including a focusing optical system is laterally inserted. The terminal head includes a positioning device accessible from outside of the housing for displacing the focusing optical system relative to the insert. The adjusting device may displace the focusing optical system in a longitudinal direction of a laser beam and at right angles to the longitudinal direction of the laser beam. This arrangement allows the focusing optical system to be readily changed and properly adjusted within the housing.