An induction tempering method allowing the tempering condition to be determined readily and the quality of a workpiece stabilized includes a heating temperature control step, and a heating time control step. The heating temperature control step includes a heating temperature control related temperature measurement step, a heating temperature adjustment step, and a heating step. The heating time control step includes a heating time control related temperature measurement step, a heating time adjustment step, and a heating end step. At the heating time adjustment step, a tempering time t to determine the timing in ending heating of the workpiece is calculated based on the following equation (A). H=a·log(t)+b·(1/T)+c  (A) H: hardness of workpiece; t: tempering time; T: temperature of workpiece; a, b, c: constant.