The invention discloses a concentric correcting device of a fettling machine. The concentric correcting device comprises an upright post, wherein a flat plate is fixed at the upper end of the upright post; a sliding plate capable of moving front and back relative to the flat plate is arranged above the flat plate; a green body longitudinal positioning device is arranged in front of the sliding plate; a rotatable correcting disc for correcting the bottom of a green body, a green body scraping plate for correcting the outer edge of the top of the green body, a first driving device and a first transmission device are mounted on the sliding plate; the first driving device is linked with the correcting disc through the first transmission device. According to the concentric correcting device of the fettling machine disclosed by the invention, the labor intensity can be reduced, the damage to the edge of the green body is avoided, the quality of a product subjected to fettling is guaranteed, and the production efficiency is improved.