PURPOSE: To prevent the generation of seam flaw by heating the edge parts in the width direction of a rough sheet bar in a specified temp. range before finish rolling at the time of the finish rolling of the rough sheet bar for hot rolled sheet.

CONSTITUTION: A heated slab is roughly rolled into a rough sheet bar and, at the time of the finish rolling of this rough sheet bar, the edge parts in the width direction of the rough sheet bar is heated in the high temp. range of ≥1300°C with a device for heating edge part before finish rolling. After that, finish rolling is executed. In this way, the seam flaw that is generated on the rough sheet bar is eliminated by heating at ≥1300°C and the seam flaw after finish rolling can be reduced easily, surely, stably and drastically.