This heat-treatment device (10) comprises a table (11) whereon a circular workpiece (W) can be placed, and a pair of heat processing units (20) for heat processing the peripheral surface of the workpiece (W). This heat-treatment device (10) is used for obtaining the workpiece (W) having the desired properties by subjecting the workpiece (W) to heat processing while the pair of heat processing units (20) move in opposite directions from one another along the peripheral surface of the workpiece. This heat-treatment device (10) is constituted in such a way that a pair of rotary arms (30) movable relative to the table (11) cause the pair of heat processing units (20) to oscillate relative to the workpiece (W), thereby heat processing the peripheral surface of the workpiece (W). Adopting such a constitution allows a heat-treatment device to be obtained, whereby heat processing becomes possible over the entire circumference of the peripheral surface of the circular workpiece.
