A heating device includes a magnetic-field generating unit that generates an alternating-current magnetic field, an endless belt, and a heat transfer unit that includes a heat storage layer, a thermosensitive layer, and a diffusion layer. The thermosensitive layer extends so as to separate the magnetic-field generating unit and the heat storage layer from each other, and forms a magnetic path that allows a magnetic flux of the alternating-current magnetic field to pass therethrough in a direction in which the thermosensitive layer extends at a temperature below a Curie temperature and a magnetic path that allows the magnetic flux to extend therethrough and reach the heat storage layer at a temperature higher than or equal to the Curie temperature. The diffusion layer has a higher thermal conductivity than thermal conductivities of the thermosensitive layer and the heat storage layer, and diffusing heat of the belt.