An image forming apparatus has an image forming unit; a heating rotatable member; a magnetic flux generator for generating a magnetic flux for induction heat generation in the heating rotatable member; a controller for controlling a temperature of the heating rotatable member; a temperature detector for detecting a temperature of the heating rotatable member at a predetermined region; magnetic flux confinor for confining the magnetic flux from the magnetic flux generator in accordance with an output of the temperature detector; and a moving unit for movement the magnetic flux confinor between a magnetic-flux-confinement position and a n on-magnetic-flux-confinement position, wherein when the output of the temperature detector indicates a temperature outside a predetermined temperature range, an image forming operation is interrupted, and executes operation of the moving unit to move the magnetic flux confinor to the non-magnetic-flux-confinement position and restoring operation to restore the temperature of the heating rotatable member.