An articulated arm for applying a laser beam to a treatment zone has an arm section and a horizontal pivot joint. A spring arrangement acts on the pivot joint and has a cam disk and a pressure member following the cam disk contour as the arm section pivots. The arm section has, relative to a vertical direction, positive and negative pivot angle ranges. In the positive range the spring arrangement relieves the pivot joint from weight forces. When a resting angle in the negative range is reached the articulated arm rests in a support device. A total moment resulting from a weight force moment of the articulated arm and a restoring moment of the spring arrangement acts on the articulated arm about the pivot joint cam disk contour and spring pretension are matched such that for the resting angle the total moment is oriented toward the support device.
