Fixing device and image forming device

An image forming device comprising:

• a heater,
• a pressurizer forming a nip section by making contact with the heater so that fixing of a image is performed for the sheet passing through the nip section,
• a controller for controlling the surface temperature of the heater so that the surface temperature of the heater becomes a predetermined set temperature,
• an amount of decrease detector for detecting an amount of decrease in the surface temperature of the pressurizer between before and after the passing of the sheet through the nip section,
• a determiner for specifying a required temperature required to perform the fixing for the sheet on the basis of the amount of decrease and for determining whether the set temperature is acceptable as the required temperature, and
• a temperature compensator for correcting the set temperature so that the set temperature is acceptable as the required temperature in the case that the determiner has determined that the set temperature is not acceptable as the required temperature.