PURPOSE: To remarkably reduce the generation of skid marks by arranging a skid beam provided with an auxiliary heating mechanism for heating the lower surface of a billet around the contact part with a skid button.

CONSTITUTION: The billet 17 of the skid button 4 is at a low temp. as compared with the temp. of the atmosphere in the heating furnace 15. Accordingly, an auxiliary heating mechanism for heating the lower surface of the billet 17 is provided separately from a burner for heating the inside of the main body of the heating furnace 15 between the skid buttons 4 arranged on the upper surface of the skid beam 1 at regular intervals. The region around the contact surface between the billet 17 and the skid button 4 is heated by the mechanism. The temp. of the contact part with the skid button 4 is increased by the auxiliary heating, and the generation of skid marks is remarkably reduced.