A heating apparatus includes a cylindrical film, a plurality of heating elements arranged inside the cylindrical film along a longitudinal direction thereof, a plurality of thermometers each configured to measure temperature of one of the heating elements, a power supply, a controller configured to control the power supply to supply electrical power to the heating elements according to the temperature measured by the thermometers, and a plurality of thermostats each configured to measure temperature of one of the heating elements and configured to interrupt the electrical power supplied to the heating element when the measured temperature exceeds a predetermined value. The thermometers and the thermostats are alternately arranged along the longitudinal direction.