An image forming apparatus includes a fixing device to fix a toner image on a recording medium by applying heat. Such a fixing device includes at least a magnetic flux generator, a heat generating roller, a magnetic shunt layer, and a protective layer. The magnetic flux generator is configured to generate magnetic flux. The heat generating roller including a heat generating layer is configured to generate heat by the magnetic flux. The magnetic shunt layer may be formed independently of the heat generating layer. The protective layer is provided on an inner surface of the magnetic shunt layer and configured to cover a crack formed in the magnetic shunt layer during fabrication of the magnetic shunt layer. An image is fixed onto the recording medium by the heat from the heat generating roller. Alternatively, the magnetic shunt layer may be integrally provided with the heat generating layer.