This paper describes the practical design of a SCR inverter which is suposed to be very much suitable for high frequency induction heating power source. In this design an optimum control technique was applied to maintain constant output power and constant power factor to various heating load by the use of frequency control. Some appreciable characteristics was obtained for some design guide of large ndstrial heating power sources by the test of the 3KHz, 3KW inverter which was designed in this study.