Abstract: An induction heating apparatus for utilizing electromagnetic induction to heat a workpiece. The apparatus includes a pair of heating coil units disposed in spaced-parallel relation to permit transportion of the workpiece between the heating coil units. Each of the heating coil units includes a main heating coil and an auxiliary heating coil disposed at a position adjacent to the main heating coil. The main heating coil has a plurality of spaced-parallel transverse conductors connected in series and produces magnetic field crossing the workpiece, causing heating when supplied with a high- or intermediate-frequency alternating current. The auxiliary heating coil includes a pair of series connected longitudinal conductors placed at positions facing to the workpiece at a small distance inside from the respective opposite side edges of the workpiece.