A power converter controlling apparatus that can prevent burnout caused by overcurrent and/or overvoltage generated by low power index operation or output short circuit in a high frequency power converter employing a digital controlling method, and a method thereof. The power converter controlling apparatus includes a digital controller which outputs a gate signal for controlling intermittent operation of a predetermined switch based on inputted control data, a detector which generates a detection signal in response to generation of overcurrent and/or overvoltage, and a registration maintenance unit for maintaining a state where the output of the gate signal is shut off, when the detection signal is generated.