THERMAL FIXING DEVICE

PROBLEM TO BE SOLVED: To provide a thermal fixing device constituted so that temperature rise is suppressed and danger such as firing is prevented from occurring by detecting abnormality (suppressing time lag) at an early stage when the temperature of a fixing roller excessively rises because the abnormality of the temperature control is caused. SOLUTION: The fixing roller 1 is provided with a releasing layer 11 outside a meatal-made roller core bar 12 and an insulating layer 13 inside the core bar 12. Besides, a heating layer 14 is formed inside the layer 13. Then, a safety device 21 composed of a thermostat and a temperature fuse is installed at the surface of the roller 1. However, the safety device 21 is arranged at a position where it is opposed to the heating pattern 14a of the layer 14.