An image fixing device for fixing an image on a sheet includes a rotatable fixing film, a heater, a rotatable pressing member, a holding member, and a metal sheet. The heater is provided on an inner surface of the fixing belt. The rotatable pressing member is provided in contact with an outer peripheral surface of the film to press against the heater through the film, thus forming a nip configured to nip and feed the sheet. The holding member includes a guide portion configured to guide the rotation of the fixing film and to hold the heater. The metal sheet covers the heater and an area of guide portion slidable relative to an inner surface of the fixing film. The metal sheet has a thermal conductivity ≥10W/(m·° C.) and has a thickness more than 0 μm and not more than 50 μm.