An inductive heating device for uniformly heating a workpiece at rest has in one embodiment of the invention a plurality of heating coil units (31 to 36) disposed so as to surround the workpiece (21). The heating coil units (31 to 36) are connected in parallel to a power source, and a transformer may be used to vary the voltage across the terminals of the outermost units to increase the current flowing through these outermost units. The device, therefore, has a very short insufficient heating temperature zones attributable to end magnetic flux effects.
In another embodiment using a non-divided coil, the end effect may be reduced by adjusting the relationship between the distance between the end of the coil and the end of the workpiece and the clearance between the coil and the workpiece.