In this paper, the influence of heat generated in profile milling on the thermal behavior of a workpiece (a disk) is analyzed theoretically. Applying Duhamel's theorem to the results of an instantaneous heat source problem, the theoretical equations of the thermal behavior for a moving heat source problem are easily derived. This method is confirmed using thermoelastic displacement potential. Comparing the temperature variations observed in an experiment with the theoretical values, the amount of heat input to a disk is estimated. Then, thermal stresses and deformations are computed numerically using actual values of physical constants of the workpiece. The numerical results on deformation are in good agreement with the experimental results, and it is concluded that the theoretical equations obtained are useful for predicting the thermal behavior of a workpiece.