According to an embodiment of the present invention, a heat treatment system is provided. The heat treatment system includes a heating unit, a heat treatment condition memory unit, a power change model memory unit, a heat treatment change model memory unit, a heat treatment result reception unit, and an optimal temperature calculation unit. In the heat treatment system, the optimal temperature calculation unit calculates the power of the heating unit at a corresponding temperature based on the model stored in the power change model memory unit and the calculated temperature, and an optimal temperature is a temperature at which a heat treatment result is closest to the targeted heat treatment result within a range in which the calculated power of the heating unit is not saturated.