This paper presents the problem of optimal control of induction heating process of the metal billets before the operation of pressure treatment. Problem setting and the solution method of the optimal control problem of start induction heating installation according to the criteria of maximum heating accuracy were proposed. The results and their analysis for the investigated models of induction heating process are given. It is shown that optimal control according to the criterion of heating accuracy converges to the control in the steady state. The analysis of the temperature field by the volume of the heated workpiece in the process of optimal control of its average temperature during the initial start of the induction heater according to the above algorithms is presented.