A rotatable endless fixing belt configured to fix a toner image borne on a recording material includes a base body and a polyimide layer. The polyimide layer is formed on an inner-circumferential-surface of the base body and configured to slide on a backup member in contact with the backup member. The polyimide layer includes filler having shape anisotropy. An orientation ratio of the filler inclined with respect to a generating line of the fixing belt by a predetermined angle or less is smaller in a first area than in a second area in a cross section of the fixing belt taken along the generating line of the fixing belt, the first area being an area formed in an inner-circumferential-surface side of the polyimide layer in a thickness direction, the second area being an area formed in a base-body side of the polyimide layer in the thickness direction.