The invention discloses a grinding machine. The grinding machine comprises a machine frame. The machine frame is provided with at least one grinding mechanism. Each grinding mechanism comprises a drive grinding disc, wherein the drive grinding disc is connected with a motor through a transmission mechanism and internally provided with at least two driven grinding discs of cylindrical structures, gear rings are arranged on the outer circumferential faces of the driven grinding discs, and a center gear is arranged in the center of the drive grinding disc; and the gear rings on the driven grinding discs are meshed with the center gear, and the driven grinding discs are further connected with a clamping jaw used for limiting the driven grinding discs. According to the grinding machine, the gear rings are arranged on the outer circumferential faces of the driven grinding discs, the center gears are arranged in the centers of the drive grinding discs, accordingly, it can be guaranteed that the rotating speed of the three driven grinding discs in each grinding mechanism is the same in the grinding process, and even and smooth workpiece grinding can be effectively guaranteed.