A fixing device that fixes a toner image carried on a transfer sheet onto the transfer sheet includes a fixing belt that relatively moves, with its surface being in contact with the toner image during the fixing operation, with respect to the transfer sheet, surface information detecting devices that determine surface information of the fixing belt, a surface condition changing roller that is arranged so as to be capable of coming into contact with and separating from the fixing belt and abrades the surface of the fixing belt in contact with the fixing belt, and a surface condition changing controller that controls the contact and separation of the surface condition changing roller with and from the fixing belt based on detection results obtained by the surface information detecting devices.