The invention discloses a cylindrical mixer which is used for solving the problem that the structure of existing cylindrical mixers can not be largely improved. The cylindrical mixer comprises a cylinder with openings at two ends, a ring gear is hooped on the outer circumference of the cylinder, a motor arranged outside the cylinder is connected with a transmission gear by a speed reducer, and the transmission gear is matched with the ring gear; the front and the rear of the cylinder are provided with a feeding conveyer and a discharge conveyer; a central shaft with two ends extending outsidethe cylinder is arranged inside the cylinder, the central shaft is connected with the cylinder by a collecting mechanism, the two ends of the central shaft are connected with a bearing seat by a bearing, and the bearing seat is fixed on a bracing structure. The cylindrical mixer is applicable to mixing iron making materials into balls.