A fixing device includes a magnetic flux generating section having a coil
which generates a magnetic flux when applying current, a fixing roller
having a heat generating layer having a thickness of 100 .mu.m or less
formed along an outer peripheral surface of the fixing roller for
generating heat through electromagnetic induction by the magnetic flux, a
capacitor connected in series to the coil to constitute a series resonant
circuit, and high frequency power supply circuits for applying voltage
having a certain drive frequency to the series resonant circuit so as to
make the fixing roller generate heat through the magnetic flux generating
section. An image is fixed onto a sheet, which is transported in a state
of being in pressure-contact with the outer peripheral surface of the
fixing roller, by heat from the heat generating layer of the fixing
roller.