A fixing device which fixes a toner image borne on a recording medium includes a rotatable fixing roll member, a rotatable tension roll member, a rotating fixing belt member stretched between the fixing roll member and the tension roll member, a heater which heats the fixing belt member, a pressing member which presses a portion of the fixing roll member around which the fixing belt member is wound to form a nip part, and a belt moving direction changing member which is interposed between the fixing belt member and the fixing roll member on a downstream side of the nip part, and changes a moving direction of the fixing belt member. Width “Wbe” of the fixing belt member, width “Wpr” of the pressing member, and width “Wpe” of the belt moving direction changing member are set to satisfy the following relation: Wpr≦Wbe