A heating device for heating, by electromagnetic induction heating, a heating member for a fixing device for use in an image forming apparatus, which fixing device is for heating and fixing an image on a recording material while nipping and transporting the recording material, the heating device comprising: an exciting coil that is disposed along the heating member and is configured to generate a first alternating magnetic flux to heat the heating member by the electromagnetic induction heating; and a demagnetizing circuit (1, 11, 12) including: a demagnetizing coil that encircles part of the first alternating magnetic flux and is configured to generate an electro-motive force that generates a second alternating magnetic flux in a direction to cancel the first alternating magnetic flux; a switch configured to open and close the demagnetizing coil; and a demagnetizing regulator configured to adjust the second alternating magnetic flux by adjusting the magnitude of a current to be generated in the demagnetizing coil; characterised in that: the demagnetizing regulator includes a component that is one of: a variable resistive element, a diode element configured to half-wave rectify a current in the demagnetizing coil and a capacitor configured to change impedance; wherein the component is disposed in series with the demagnetizing coil so as to adjust the second alternating magnetic flux, wherein the component is between the switch and the demagnetizing coil. an exciting coil that is disposed along the heating member and is configured to generate a first alternating magnetic flux to heat the heating member by the electromagnetic induction heating; and a demagnetizing circuit (1, 11, 12) including: a demagnetizing coil that encircles part of the first alternating magnetic flux and is configured to generate an electro-motive force that generates a second alternating magnetic flux in a direction to cancel the first alternating magnetic flux; a switch configured to open and close the demagnetizing coil; and a demagnetizing regulator configured to adjust the second alternating magnetic flux by adjusting the magnitude of a current to be generated in the demagnetizing coil; characterised in that: the demagnetizing regulator includes a component that is one of: a variable resistive element, a diode element configured to half-wave rectify a current in the demagnetizing coil and a capacitor configured to change impedance; wherein the component is disposed in series with the demagnetizing coil so as to adjust the second alternating magnetic flux, wherein the component is between the switch and the demagnetizing coil. a demagnetizing coil that encircles part of the first alternating magnetic flux and is configured to generate an electro-motive force that generates a second alternating magnetic flux in a direction to cancel the first alternating magnetic flux; a switch configured to open and close the demagnetizing coil; and a demagnetizing regulator configured to adjust the second alternating magnetic flux by adjusting the magnitude of a current to be generated in the demagnetizing coil; the demagnetizing regulator includes a component that is one of: a variable resistive element, a diode element configured to half-wave rectify a current in the demagnetizing coil and a capacitor configured to change impedance; wherein the component is disposed in series with the demagnetizing coil so as to adjust the second alternating magnetic flux, wherein the component is between the switch and the demagnetizing coil.