The present invention relates to a blade structure for a grass cutter. According to the present invention, the auxiliary blade provided to be inclined toward the power transmission part is coupled at the lower part of the main blade, and thus grass wound around the power transmission part during grass cutting is naturally cut by the auxiliary blade and grass cutting can be expedited and facilitated. The blade structure for a grass cutter according to the present invention for solving the above-described problem is a blade structure for a grass cutter cutting grass and connected to a motor and coupled with the power transmission part transmitting power, comprising a main blade having in a central portion a connection hub formed with a first connection groove connected to a power shaft of the power transmission portion and a blade provided at both ends of the connection hub in the width direction an auxiliary blade including a body coupled with the power shaft, positioned below the connection hub, and having in a central portion a second connecting groove coaxial with the first connecting groove and a bending blade portion in which a first auxiliary cutter blade is formed at both ends in the width direction and protruding upwards while being bent at both ends of the body in the front-rear direction a holder unit including an upper holder provided at an upper portion of the main blade and a lower holder provided at a lower portion of the auxiliary blade to fix the main blade and the auxiliary blade and a fixing part coupled to the power shaft below the lower holder and for coupling between the main blade, the auxiliary blade and the holder part and the power shaft.본 발명은 주칼날의 하부에 동력전달부측으로 경사지게 구비되는 보조칼날이 결합됨에 따라, 벌초 중에 동력전달부측에 감기는 풀이 보조칼날에 의해 자연적으로 절단되어, 벌초가 더욱 쉽고 빠르게 이루어지도록 하는 예초기용 칼날구조에 관한 것이다. 상기 과제를 해결하기 위한 본 발명의 예초기용 칼날구조는 모터와 연결되어 동력을 전달하는 동력전달부와 결합되며, 풀을 베도록 이루어지는 예초기용 칼날구조에 있어서, 중심부에 상기 동력전달부의 동력축과 연결되는 제 1연결홈이 형성되는 연결허브 및 상기 연결허브의 폭방향 양단에 구비되는 칼날부가 형성되는 주칼날 중심부
