Abstract: An apparatus for incising animal's intestines comprises a guide rod to be inserted into animal's intestines for guiding the intestines backward, a pair of endless belts disposed along both longitudinal sides of the guide rod for transporting the intestines backward, an incising blade disposed above and a cutting blade disposed below the guide rod respectively for longitudinally incising an upper side of the intestines and cutting to remove a fat layer deposited on a lower surface of them, and a cleaning means disposed downstream to the guide rod for cleaning the incised intestines. A take-drum may preferably be disposed downstream to the cleaning means. Incising treatment for animal's intestines can be automated completely.