An image forming apparatus detects that the temperature of a fixing member reaches a lower limit value at which the temperature once reduced by the start of a heating and fixing process to a paper turns to rise, after an image forming operation starts, and determines the type of the paper based on at least one of an elapsed time from a predetermined reference time point after the image forming operation starts to a time point at which it is detected that the temperature reaches the lower limit value, and a temperature difference between the temperature of the fixing member at the reference time point and the lower limit value.