Inductively heating device.

Apparatus induction heating comprising: an inverter (79) having a switching device (88), one reverse conducting device (84) connected to the switching device (88) in parallel, a heating coil (89) for heating a load (90) generating a magnetic field and a unit resonant capacitor (91; 92), wherein the inverter (79) generates a resonant current (IL) passing through the heating coil (89) activating the switching device (88); a control circuit (85) for controlling an activation time (T1) of the switching device (88), wherein the apparatus further comprises an amplifying circuit and smoothing (80; 81; 82; 87) for boosting and smoothing one DC voltage input to provide the DC boosted and smoothed to the inverter (79) voltage in order to maintain an amplitude of the resonant current (IC) passing through the switching device (88) to be equal to or greater than a predetermined value during the activation time (T1) of the switching device (88); and the control circuit (85) is designed such that, in case the load (90) is a material of high conductivity and low permeability, activates the switching device (88) during an activation time ( T1) which is higher than the resonance period of the resonant current (IC) passing through the switching device (88) or the reverse conducting device (84).