To provide an induction heat treatment apparatus which can retreat an induction heating coil, so as to keep a gap between the induction heating coil and a localized area to be heated constant, through a high-frequency induction heating operation.

The induction heat treatment apparatus 10 comprises: a workpiece driving means 11 for driving a workpiece; the induction heating coil 15 for induction-heating the workpiece 20; a supporting and moving means 14 for supporting and moving the induction heating coil 15; and a displacement measurement means 40 for measuring a thermal expansion displacement of the workpiece. The displacement measurement means 40 has a contact shoe 43 and a distance sensor 41. The contact shoe 43 is connected with a displacement detection shaft 41a of the distance sensor 41 so that the distance sensor 41 conducts heat so as to be kept into its heat-resistant temperature or lower.

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