The present invention relates to an apparatus for automatically cutting rice straw for livestock feed and a method for automatically cutting rice straw using the same capable of enabling a general domestic stock farm to directly manufacture and produce livestock feed. An apparatus for automatically cutting rice straw for livestock feed according to the present invention comprises: a main body part for including a blade entering hole and being installed to the length direction； a rice straw supply unit for being prepared in an upper part of the main body part as a box body having a rice straw inserting hole and a rice straw discharging hole, wherein the rice straw discharging hole is connected with the blade entering hole to the vertical direction and is continuously moved back and forth along the length direction of the main body part； and a rotary cutting unit for being prepared in a lower part of the rice straw supply unit, entering the blade entering hole by being rotated to the vertical direction of the movement direction of the rice straw supply unit while the rice straw supply unit is moved back and forth, and cutting rice straw. According to an apparatus for automatically cutting rice straw for livestock feed and a method for automatically cutting rice straw using the same according to the present invention, cutting, grinding, and discharging processes can be performed only by inserting rice straw, the size of the rice straw to be cut and ground can be controlled, the all process can be automatized and integrated, the processes can be performed in a small space, and a general domestic stock farm, therefore, can produce livestock feed only using a space and manpower of the stock farm.본 발명은 일반 축산농가에서 직접 축산용 조사료를 제조, 생산할 수 있게 하는 축산 사료용 볏짚 자동 세절장치와 이를 이용한 볏짚 자동 세절방법에 관한 것이다.본 발명에 따른 축산 사료용 볏짚 자동 세절장치는, 칼날출입구가 형성되어 길이방향으로 설치되는 본체부와, 볏짚투입구와 볏짚배출구가 형성된 함체이고 상기 본체부의 상부에 구비되며, 상기 함체에 형성된 볏짚배출구는 칼날출입구와 수직방향으로 연통되어 본체부의 길이방향을 따라 연속적으로 왕복이동되는 볏짚공급부, 및 상기 볏짚공급부의 하부에 구비되며,
