Provided is a heat treatment apparatus (1), including: a heating unit (2), which is configured to inductively heat a workpiece (W) to a target temperature; and a drive mechanism, which is configured to move a plurality of the coaxially held workpieces (W) relative to the heating unit (2) being in an energized state in an axial direction of the workpiece (W), wherein the heating unit (2) includes: a plurality of coil members (11) respectively including a ring-shaped coil portion (11a) arranged coaxially with the workpiece (W) so as to be capable of surrounding the workpiece (W); and a frame body (21), which is configured to support each of the plurality of coil members (11) so as to be movable in the axial direction of the workpiece while maintaining the coaxial arrangement between the coil portions (11a).