Heat treatment apparatus and heat treatment method

A heat treatment apparatus that thermally treats an annular workpiece formed of a steel material by inductively heating the workpiece, the heat treatment apparatus comprising:

• a treatment tank in which the workpiece is set and thermally treated;
• holding portions that hold the workpiece at a predetermined position;
• an induction heating coil that surrounds the workpiece to inductively heat the workpiece;
• and
• a cooling medium that cools surfaces of the workpiece during the induction heating of the workpiece,
• wherein:
• the holding portion is formed of electrically insulating ceramics or an electrically insulating synthetic resin,
• the holding portions consist of first support portions, second support portions and third support portions,
• the first support portions receive a lower surface of the workpiece,
• the second support portions suppress horizontal movement of the workpiece, the second support portions receiving an outer peripheral surface of the workpiece, and
• the third support portions suppress upward movement of the workpiece.