To provide an image forming apparatus having a fixing device of a fixing belt system that forms a high quality image without causing gloss differences despite successive passage of transfer materials.

The image forming apparatus has the fixing device 30 that thermally fixes an unfixed toner image by passing a transfer material P with the unfixed toner image thereon through a fixing nip area N between a rotating fixing belt 31 and a pressure roller 35. The image forming apparatus includes: a non-contact type partial heating means 40 disposed upstream of the fixing nip area N in the direction of the rotation of the fixing belt 31 and in the position where the contact face of the fixing belt 31 with the transfer material P is heated; a transfer material temperature detecting means 14 disposed downstream of the fixing nip area N in the direction of the transfer material conveyance and used to detect the temperature of the transfer material P; and a control means 12 for controlling a non-contact type partial heating means 40. The control means 12 exerts control such that a quantity of heat supplied to the non-contact type partial heating means 40 is altered in accordance with the detection result of the transfer material temperature detecting means 14 and transfer material information.