An induction hardening apparatus comprises heating coils (26) that inductively heat different parts of the treatment target portion (A) in an axial direction of the work (12), the work (12) and a heating coil (26) being relatively moved along a circumferential direction (R) of a treatment target portion (A). The heating coil (26) has a zigzag shape in which a bent portion (34) that is opened to one side in the axial direction and a bent portion (35) opened to the other side in the axial direction are alternately continuously arranged in opposed directions along the circumferential direction (R).
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