The instrument for the ligation of hemorrhoids or the like includes a substantially cylindrical container with a coupling for the connection of an air aspiration apparatus and a grip handle for the operator. The container is suitable for internally accommodating a hemorrhoid or the like aspirated through its open end, on which a dilated ring-like elastic ligature, to be transferred so as to throttle the "neck" of the hemorrhoid or the like, is arrangeable externally and circumferentially. The instrument is characterized in that the container is provided with a thumb-actuated hole for adjusting the pressure inside it while the aspiration apparatus is operating.