To provide a power output method of an induction heating type alloying furnace which can alleviate the total capacity of the induction heating type alloying furnace while satisfying the power output characteristic requirement for the induction heating type alloying furnace.

In the power output method of the induction heating type alloying furnace 14 in subjecting a hot dip metal coating layer formed on the surface of a steel sheet 11 discharged from a heat treatment furnace 12 to alloying treatments by using the furnace 14 equipped with a plurality of induction heaters 22 and 23, the power output characteristic requirements required for the furnace 14 are previously determined according to the width of the steel sheet 11 to be treated based on the treatment capability characteristic of the furnace 12 and the maximum power output points of the respective heaters 22 and 23 are respectively set at the fluctuation range of the width of the steel sheet 11 and the overall power output characteristics which are the summation of the power output characteristics of the heaters 22 and 23 are substantially matched with the power output characteristic requirement.