The utility model relates to an ascending tube arranged between a steel ladle and a vacuum chamber. A first row of through holes and a second row of through holes which are in axial displacement with respect to the first row of through holes are formed in the radial direction of the ascending tube, and a threaded groove channel is formed in the inner surface of each through hole of the first row of through holes and the second row of through holes. According to the ascending tube disclosed by the utility model, by virtue of a through hole arrangement mode, a phenomenon that gas jet flow produces energy loss in a central area of the ascending tube can be avoided, the utilization rate of gas can be increased, and circulating conditions of molten steel can be improved.