The present disclosure relates to an induction heating device comprising: a heating coil provided in a main body; a knob switch, detachable from and attachable to a knob area formed on one surface of the main body, for adjusting a heating power of the heating coil by rotation when attached to the knob area; a resonance detecting unit for outputting a frequency pulse corresponding to an impedance inflection point that varies according to a degree of rotation of the knob switch; and a controller for controlling the heating power of the heating coil according to the frequency pulse.