To provide an induction heating quenching method for heating uniformly a plate member, having a concavo-convex part on a flat surface.

In an induction heating quenching of a work (ring-shape round plate member) W, having a concave part 3, a convex part 2, and a rim 4 on a flat surface 1, an induction heating coil 20 made of a flat plate ring conductor 21, covering the heating face of the work W on the lower face side of the work W and an induction heating coil 10, made of a ring conductor with rim having a flat plate portion 11 of flat plate covering the heating face and a cylindrical portion 12 surrounding the upper periphery of the rim 4 on the upper face side of the work are arranged with a spacing, capable of inserting the work; and by moving the work W so that its lower face has a prescribed spacing with the heating coil 20, the lower face is heated; and furthermore, by moving the work W so that the upper face has a prescribed spacing with the heating coil 10, the upper face and the outer periphery of of the ring 4 are heated and quenched.

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