An inductive heating device comprising: a smoothing part, a first switching element, a second switching element, a third switching element and a fourth switching element forming a full-bridge which is connected to the smoothing part, wherein the first and second switching elements are connected to each other at a connection point to form a first leg of the full-bridge which is connected to the smoothing part and the third and fourth switching elements are connected to each other at a connection point to form a second leg of the full-bridge which is connected to the smoothing part, and a resonance circuit comprising a heating coil for heating a material to be heated inductively being in series with a resonance capacitor, the resonance circuit being connected between the connection point of the first and second switching elements and the connection point of the third and fourth switching elements, characterized by a control part for controlling to vary the magnitude of the resonance current to be supplied in the resonance circuit, between a first mode for controlling and operating to conduct the first and second switching element alternately in a state of conducting either one of the third and fourth switching elements and cutting off the other, and a second mode for conducting the first and fourth switching elements and conducting the second and third switching elements alternately, wherein the first and second switching elements are of unipolar type, and the third and fourth switching elements are of bipolar type, and the control part operates in the first mode when heating a material made of aluminum, and operates in the second mode when heating a material made of iron. a smoothing part, a first switching element, a second switching element, a third switching element and a fourth switching element forming a full-bridge which is connected to the smoothing part, wherein the first and second switching elements are connected to each other at a connection point to form a first leg of the full-bridge which is connected to the smoothing part and the third and fourth switching elements are connected to each other at a connection point to form a second leg of the full-bridge which is connected to the smoothing part, and a resonance circuit comprising a heating coil for heating a material to be heated inductively being in series with a resonance capacitor, the resonance circuit being connected between the connection point of the first and second switching elements and the connection point of the third and fourth switching elements, a control part for controlling to vary the magnitude of the resonance current to be supplied in the resonance circuit, between a first mode for controlling and operating to conduct the first and second switching element alternately in a state of conducting either one of the third and fourth switching elements and cutting off the other, and a second mode for conducting the first and fourth switching elements and conducting the second and third switching elements alternately, wherein the first and second switching elements are of unipolar type, and the third and fourth switching elements are of bipolar type, and the control part operates in the first mode when heating a material made of aluminum, and operates in the second mode when heating a material made of iron.