The utility model relates to a grounding device. The grounding device comprises a grounding box (2), a grounding rod (4), an insertion ring (3) and a nut (1). The insertion ring (3) is connected onto the corresponding wall of the grounding box (2). The grounding rod (4) is inserted into the insertion ring (3). The nut (1) goes through the grounding rod (4) and is in spiral connection with the insertion ring (3). A step end face (1) is arranged on the grounding rod (4). The step end face (1) corresponds to the outer side end face (31) of the insertion ring (3). The nut (1) is screwed up, the step end face (1) is pressed against the outer side end face (31) of the insertion ring (3), and the two end faces are connected. The step end face arranged on the grounding rod is pressed against the end face of the insertion ring, the grounding rod contacts a cylindrical surface and an inner ring surface of the insertion ring (3) and the contact area of the cylindrical surface and the inner ring surface is increased, the contact resistance is decreased, reliable discharging can be carried out when the device is grounded, and operation personnel can carry out device detection under a very safe environment.