PURPOSE: To heat uniformly only circumferential surface of material to be heated and to prevent wear of a furnace core tube, by supporting material to be heated introduced through a chute by a supporting means then discharging it outside the furnace core tube in the vertical furnace core tube of an induction heating furnace.

CONSTITUTION: A billet 1 being material to be heated supplied from supplying chutes 13, 14 is mounted and carried on a belt 20 of a conveyer 12, charged in the furnace core tube 15a arranged so that the shaft core becomes parallel to vertical line in the induction heating furnace 15 through the chute 17, and supported on a supporting base 28 of the supporting means 16. Next, high or medium frequency source (figure is omitted) is connected to a coil 15b wound around circumference of the tube 15a, to heat the billet 1 for a prescribed time. Thereafter, the base 28 on a cover 27 is lowered by operating a cylinder 29 whose base end is attached to a case 11 freely turnably to slant the billet 1 mounted thereon and to carry it on a chute 18 and to transfer it to next forging stage.