A DC-DC converter circuit for stabilizing the output voltage of the secondary side by correcting the input voltage by using a simple circuit, where no state measurement circuit is necessary at the secondary side. The circuit includes a transformer; a switching circuit including a main switching element which is connected to the primary winding of the transformer in series and has a control terminal for controlling the main switching element, wherein the main switching element is PWM-controlled so as to stabilize an output voltage of the secondary side; a driving circuit for generating PWM driving pulses; and a correction circuit for outputting a voltage whose level is in inverse proportion to an input voltage of the DC-DC converter circuit. An output of the driving circuit is connected to the control terminal of the main switching element and to the correction circuit.