Abstract: Described herein are a device and a method for the treatment of varicose veins via laser radiation, and in particular using a holmium laser. The radiation of a laser source (5) is injected in a fiber (3) that can be inserted in the vessel to be treated. The laser source emits a radiation such as to cause a hyalinizing sclerosis with structural modifications both to the fibers of the collagen (shrinkage) and to the extracellular matrix of the median coat of the vein by the photothermal effect, substantially without thermal stress of the morphological component of the tunica media and of the tunica intima.