An image heating apparatus includes: a rotatable member; and a first heater and a second heater, for heating the rotatable member. The ratio of the second-heater heat generation amount at an end portion thereof to that at a central portion thereof is larger than that of the first heater at an end portion thereof to that at a central portion thereof with respect to the longitudinal direction. The apparatus also includes: a back-up member; a sensor; and an electric power supply controller capable of controlling the heaters independently. The controller effects switching to decrease the ratio of the power to the second heater to the power to the first heater, when heating a small width sheet. Immediately after the switching, the power to the second heater is smaller and the power to the first heater is larger than those immediately before the switching.