[en] The aim of the invention is to simplify the RF power supply circuit of a linear accelerator by means of: removal of separation of the linear accelerator resonator into two equal portions; stabilization of the RF field in the resonator by means of the feedback on the reflected wave; simplification of the RF generator tuning; decrease of the operating power level and refine of the stabilization accuracy. For this purpose the resonator is connected to two identical outputs of the RF generator terminal stage with the aid of the directional couplers with the power division factor of 1/2. The other output arms of the directional couplers are connected with the resonator via non-interacting phase shifters with non-interacting phase shift. The arms of the directional couplers are coupled to a smooth attenuator which is connected with a power summation T-bridge placed between the preterminal and terminal stages of the generator