To see that a synchronous rectification type DC-DC converter stops without a coil connected to an output terminal and a capacitor causing resonation, without being provided with a complicated circuit, when shifting from its operation state to its stop state, and that a protective element or a parasitic element is not broken or that a circuit does not cause malfunction.

The synchronous rectification type DC-DC converter includes a switching element (SW1) for drive that lets a current flow to an inductor, a switching element (SW2) for rectification, and a smoothing capacitor which is connected to an output terminal. A switch element (SW3) for discharge is provided between an output terminal and a grounding point, and when stopping its voltage converting operation, the switch element for discharge is switched on while the switching element for drive and the switching element for rectification are switched off, and the smoothing capacitor is discharged to lower its output voltage.