An infrared sensor 26 includes an infrared detection element 26a which is provided on a lower side of a top plate 2 to detect an amount of infrared light radiated from a heated object 20 and an amplifier 26b operable to amplify a signal detected by the infrared detection element 26a. The infrared sensor 26 outputs an initial detection value having a substantially constant magnitude with respect to the temperature of the heated object 20 when the temperature of the heated object 20 is lower than a detection lower limit temperature, and outputs a detection signal having magnitude and rate of increase which become larger as the temperature of the heated object 20 becomes higher in the vicinity of a control temperature range in which the control unit 29 controls the output of the induction heating coils 21a and 21b to perform temperature control of the heated object 20. The control unit 29 includes a storage unit 29a operable to measure and store the initial detection value, and reduces the output of the induction heating coils 21a and 21b or stops the heating when an increased amount of the output value of the infrared sensor 26 with respect to the initial detection value stored in the storage unit 29a becomes greater than or equal to a predetermined value.
