An image heating device is provided with a tubular film, and a unit placed inside the film. The unit includes a heater in contact with an inner surface of the film, a supporting member supporting the heater, and a highly thermal conductive member. The highly thermal conductive member placed between the heater and the supporting member and in contact with the heater. The unit is configured such that when the unit is viewed from a side where a surface of the heater is in contact with the film, at least a portion of the highly thermal conductive member is visible without being hidden behind the heater.