A fixing apparatus includes a tubular film and a heater in contact with an inner surface of the film. The heater includes a long thin substrate, a first heat generation resistor extending in a longitudinal direction of the substrate, a second heat generation resistor extending in the longitudinal direction of the substrate, and a conductor electrically connecting the first heat generation resistor and the second heat generation resistor to each other. At least part of the conductor is disposed in an area, in the longitudinal direction, in which the first heat generation resistor is disposed. In a range of 25° C. to 900° C., the conductor has a resistance lower than a total resistance of the first heat generation resistor and the second heat generation resistor. The conductor has a temperature coefficient of resistance larger than a temperature coefficient of resistance of the first heat generation resistor.