An induction heat treatment method with which temperature control is enabled, condition setting is easy, and the quality of a treatment object can be stabilized includes: a data acquiring step of heating and quench-hardening a sample of the treatment object to thereby acquire process data; a storing step of storing the process data; a checking step of checking the power supply output transition data and the quenching timing data as to validity based on the temperature transition data stored in the storing step; and a mass production step of performing heat treatment of the treatment object in accordance with the power supply output transition data and the quenching timing data stored in the storing step and checked as to validity in the checking step.