A fixing apparatus has a coil for forming a magnetic field; a fixing rotatable member for fixing an unfixed toner image carried on a recording material thereon by heat generated by eddy currents which is generated by the magnetic field; an electric power supply control for controlling electric power supply to the coil; and a rotating mechanism for rotating the fixing rotatable member. The method further comprises monitoring, by a health service of the shared kernel, the first operating system and a first application executing within the first userland; and monitoring, by the health service, the second operating system and a second application executing within the second userland. In this case, when the atmospheric pressure control is abnormal, it is judged a major trouble, and a mode to ensure ventilation in an elevator car is selected.