Abstract: An immersion nozzle which comprises a twisted tape-shaped part (1) for allowing a flow of molten steel to swirl in the nozzle. This part is applicable to both of straight pipe type and double port type immersion nozzles, and a double port type immersion nozzle (12) is constructed to be bottomless to eliminate a problem associated with inclusions that may attached to bottom surface. Further, in the immersion nozzle, an inner wall surface of a discharge port is shaped to be arcuately divergent in longitudinal cross section, whereby the quality of cast pieces are further enhanced. When the immersion nozzle additionally includes a construction (15) for blowing a gas into a flow of molten steel which is made by the twisted tape-shaped part to swirl, effects of catching, carrying and floating inclusions are further enhanced.