PURPOSE: To reduce scarfing loss and a space required for installing the whole line by forming a round billet with dimensional accuracy by a blooming mill and installing a hot scarfer at the front stage of the mill, in a manufacture by heating a red-hot continuously-cast bloom as it is to bloom the heated bloom.

CONSTITUTION: A continuously cast bloom is charged into a heating furnace while maintaining its red-hot state and is heated to a rolling temperature or soaked, and then the bloom E is descaled and hot scarfed. Next, the bloom is rolled into a billet having a polygonal cross section more multangular in shape than an octagonal one by a blooming mill, and is rolled successively by a planetary skew rolling mill (PWS). In this system, by providing a hot scarfer to the front stage of the mill, a round billet manufactured by the mill can be directly supplied to the PWS by eliminating an intermediate mill.