The present invention intends to eliminate the need for a temperature detecting element adapted to measure the temperature of a roll main body, and provides an induction heated roll apparatus 100 including: a roll main body 2; a magnetic flux generating mechanism 3 including an iron core 31 and a winding 32; and a power supply circuit 5 provided with a control element 4 adapted to control AC current or AC voltage. The induction heated roll apparatus 100 is configured to calculate the temperature of the roll main body 2 using an AC current value obtained by an AC current detecting part adapted to detect AC current flowing through the winding 32, an AC voltage value obtained by an AC voltage detecting part adapted to detect AC voltage applied to the winding 32, a power factor obtained by a power factor detecting part adapted to detect the power factor of an induction heated roll including the roll main body 2 and the magnetic flux generating mechanism, a winding resistance value of the winding 32, and excitation resistance obtained from characteristics of the relationship between magnetic flux density and the excitation resistance of a magnetic circuit configured to include the iron core 31 and the roll main body 2 as parameters.