PURPOSE: In an induction heater for heating forging steel material at a specified temperature, reheater is installed at backstream of the main heater so as to prevent deficient steel billet production due to insufficient heating.

CONSTITUTION: A billet 3 on the bench 5 is pushed by the push bar 9 and charged into the main heater 4. The billet 3 passes through the main heater 4 while being heated by induction heater coils 1a to 1d to the outlet. The temperature of the billet 3 is detected by the sensor 10 and when it is heated to a specified temperature, it passes through the reheater 15 to be transferred to next forging process. If the temperature of the billet 3 is lower than the specified value, it is stopped by the holder 14 in the reheater 15. At the same time, the induction coil 12 is acturated to heat the billet 3 until the detector 16 confirms that the temperature is reached to a specified value. Then, the billet 3 is released and sent to the next process. Thus, the process eliniates the loss material, enabling all billet material transmission to next forging stage.