A method for heat-treating a ring-shaped member comprising the steps of: forming, by relatively rotating an induction heating member arranged to face part of a circumferential surface of a ring-shaped member made of steel for induction-heating said ring-shaped member along the circumferential direction of said ring-shaped member, an annular heated region in said ring-shaped member, said heated region having said steel austenitized therein; and simultaneously cooling a whole of said heated region to a temperature of not more than an M s point, the step of forming said heated region including a preheating step, a heating step and a supercooling step; wherein in the preheating step, a surface layer region of said formed ring-shaped member including said circumferential surface is heated, wherein the preheating step is ended when or before rolling contact surface has been heated to the temperature of not less than the A 1 point; wherein in the heating step, the heating is performed until a location facing the induction heating member and corresponding to a desired hardening depth has a temperature exceeding the temperature of the A 1 point; wherein in a supercooling step, said ring-shaped member continues to be rotated, whereby the region of said circumferential surface heated in the heating step is moved away from the location facing the induction heating member; and wherein in the step of forming said heated region, by rotating said ring-shaped member for a plurality of times at a speed less than that in the preheating step after completion of the preheating step, the heating being performed to repeatedly change over for a plurality of times between a state in which each region of said circumferential surface has a temperature exceeding a temperature of an A 1 point and a state in which each region of said circumferential surface has a temperature that is less than the temperature of the A 1 point and that maintains a supercooled austenite state. forming, by relatively rotating an induction heating member arranged to face part of a circumferential surface of a ring-shaped member made of steel for induction-heating said ring-shaped member along the circumferential direction of said ring-shaped member, an annular heated region in said ring-shaped member, said heated region having said steel austenitized therein; and simultaneously cooling a whole of said heated region to a temperature of not more than an M s point, the step of forming said heated region including a preheating step, a heating step and a supercooling step; wherein in the preheating step, a surface layer region of said formed ring-shaped member including said circumferential surface is heated, wherein the preheating step is ended when or before rolling contact surface has been heated to the temperature of not less than the A 1 point; wherein in the heating step, the heating is performed until a location facing the induction heating member and corresponding to a desired hardening depth has a temperature exceeding the temperature of the A 1 point; wherein in a supercooling step, said ring-shaped member continues to be rotated, whereby the region of said circumferential surface heated in the heating step is moved away from the location facing the induction heating member; and wherein in the step of forming said heated region, by rotating said ring-shaped member for a plurality of times at a speed less than that in the preheating step after completion of the preheating step, the heating being performed to repeatedly change over for a plurality of times between a state in which each region of said circumferential surface has a temperature exceeding a temperature of an A 1 point and a state in which each region of said circumferential surface has a temperature that is less than the temperature of the A 1 point and that maintains a supercooled austenite state.