The present invention relates to a grounding apparatus of a harrow for a tractor and, more specifically, to a grounding apparatus of a harrow for a tractor, wherein a grounding plate is provided below a central plate or an external plate to prevent the central plate and the external plate from being immersed in the ground when harrowing is performed on the rice field, thereby achieving smooth drainage, preventing the slipping of soil, and cleanly fishing the bottom surface of the rice field. To this end, the harrow of the tractor of the present invention comprises: a harrow fame (12) and an elevation cylinder (14) of which front ends are connected to a rotary (10)； a central plate (20) coupled to a rear end of the harrow frame (12), and elevated and lowered by the elevation cylinder (14)； and external plates (25) installed on left and right outsides of the central plate (20). Here, a grounding plate frame (30) is detachably installed at a grounding plate bracket (50) formed at the central part (20) or the external plate (25) by a coupling unit, below the central plate (20) or the external plate (25). In addition, a grounding plate (40) is coupled to the lower end of the grounding plate frame (30) to protrude forward of the central plate (20) or the external plate (25), and is grounded to the rice field at the time of harrowing. In order to control the installation angle of the grounding plate (40), a plurality of coupling holes (52) composed of openings or long holes are formed in the grounding plate frame (30) or the grounding plate bracket (50), and the grounding plate frame (30) and the grounding plate bracket (50) are coupled to each other by the coupling unit.본 발명은 트랙터용 써레의 접지장치에 관한 것으로, 더욱 상세하게는 중앙판 또는 외측판의 하부에 접지판을 구비함으로써 무논의 써레작업시 중앙판 및 외측판이 지면에 잠기는 것을 방지하여 원활한 배수는 물론 흙 밀림이 방지되고, 무논의 바닥면이 깔끔하게 마무리되도록 한 트랙터용 써레의 접지장치에 관한 것이다.이를 위해, 본 발명은 로타리(10)에 전단이 연결되는 써레프레임(12) 및 승강실린더(14)와, 상기 써레프레임(12)의 후단과 결합되고 승강실린더(14)에 의해 승하강되는 중앙판(20)과, 그 중앙판(20)의 좌우 외측에 설치되는 외측판(2
