A DC-DC converter includes: a first capacitor; a first switching element, a second switching element, a third switching element, and a fourth switching element sequentially connected to one another in series between both ends of the first capacitor; a second capacitor having both ends connected at a connection node of the first switching element and the second switching element and a connection node of the third switching element and the fourth switching element, respectively; and a controller configured to determine whether an overvoltage is applied to both ends of the first to fourth switching elements, respectively, based on a first sensed voltage obtained by sensing a voltage applied to the first capacitor and a second sensed voltage obtained by sensing a voltage applied to the second capacitor.