A supporting member supporting a heating member includes a lubricant storage portion storing a lubricant on an upstream side of a nip portion in a rotation direction of an endless film sliding with respect to the heating member. The supporting member further includes a lubricant supplying portion supplying the lubricant stored in the lubricant storage portion to an inner peripheral surface of the film. An amount of the lubricant supplied from the lubricant supplying portion to the inner peripheral surface of the film per unit time is larger in an area through which a small-sized recording material smaller than a maximum-sized recording material fixable by the image heating device does not pass in a longitudinal direction than in an area through which the small-sized recording material passes.