PURPOSE: To obtain a round billet being useful as seamless pipe material by starting drawing of the solidified cast billet together with dummy bar and casting molten metal flowing into a nozzle from a stopper head with inert gas injecting flow into a mold as hollow stream.

CONSTITUTION: Upper end of the dummy bar 60 is abutted on tip part in the head 31 of the stopper 30 shutting the nozzle 40 and the stopper is shifted upward together with the dummy bar, and pouring of the molten metal into doughnut-like space demarcated with the dummy bar in the mold 50, is started. Under injecting the inert gas into hollow hole in the dummy bar from the stopper head 31, the drawing of the solidified cast billet in the mold is started together with the dummy bar. After starting the drawing, the molten metal flowing into the nozzle with the injection flow of the inert gas from the tip part of the stopper head is cast into the mold as the hollow stream. By this method, the obtd. round billet is hollow body and piercing rolling process is eliminated and producing operation for seamless pipe can de efficiently executed.