To reduce contamination caused by the residue of toner and oil stuck to a temperature detection means in a fixing device.

This fixing device is provided with a fixing roller 102 rotating while being heated to fixed temperature by a halogen lamp heating element 101, a pressure roller 105 being in press contact with the roller 102, rotated by the rotation of the roller 102 and fixing an unfixed image on a recording medium 104 in cooperation with the roller 102, a temperature detecting element 107 detecting the surface temperature of the roller 102, a press-contact plate 110 holding the element 107 to be nearer to and away from the roller 102 at a position where the element 107 is made in press-contact with the surface of the roller 102 and a position where it is made away from the surface, and a cleaning means 109 arranged at a position where the element 107 is away from the roller 102 and cleaning the measuring surface of the element 107.