A temperature control apparatus of a hot-rolling mill according to the present invention extracts a high-frequency component, a medium-frequency component, and a low-frequency component from a deviation between a calculated value or a measured value of a material temperature in a temperature managing position set on an outlet side of the hot-rolling mill and a given temperature target value. The temperature control apparatus then corrects a reference value of electric power of an induction heating device set to an electric power changing device based on the high-frequency component, corrects a reference value of a cooling water flow rate set to a flow rate changing device based on the medium-frequency component, and corrects a reference value of a roll rotation speed set to a speed changing device based on the low-frequency component.