A heating apparatus includes a core; magnetic flux generating means having an
excitation
coil provided outside the core; an induction heat generating element for electromagnetic
induction heat generation using the magnetic flux generated by the magnetic flux
generating means, a heating portion for receiving a recording material and for
heating the recording material by the heat generated by the induction heat generating
element, the heating portion being elongated in a longitudinal direction crossing
with a direction in which the recording material is fed to the heating portion;
magnetic flux adjusting means for changing a distribution, in the longitudinal
direction, of densities of the magnetic flux generated by the magnetic flux generating
means in the heating portion; the magnetic flux adjusting means including a magnetic
flux shield member, and moving means for moving the magnetic flux shield member
to a position for adjusting the magnetic flux generated by the magnetic flux generating
means, the magnetic flux shield member being effective to block the magnetic flux
at a position between the core and the excitation coil.