A fixing device includes a heating member, a pressurizing member, a coil wound in a loop shape in the width direction of the heating member to generate a magnetic flux that inductively heats the heating member, and a magnetic core adjacent to the coil. The magnetic core is configured to apply the magnetic flux to an inductive heat-generating layer of the heating member. The magnetic core includes first core parts and second core parts. The first core parts are positioned to enclose the coil in a direction orthogonal to a direction in which paper is conveyed. The second core parts are placed in hollow areas formed by the loops of the coil at both ends in the direction orthogonal to the paper conveyance direction. The second core parts have a higher Curie temperature and a lower thermal capacity than the first core parts.