A DC /
DC converter according to the present invention includes a first switch connected to both ends of the DC power supply through a primary winding of a first
transformer, a second switch connected to both ends of the DC power supply through a primary winding of a second
transformer, a first series circuit connected between a node to which the primary winding of the first
transformer and one end of the first switch are connected, and another end of the first switch, the first series circuit including a first
diode, a
smoothing capacitor, and an additional winding of the first transformer, which is connected to the primary winding of the first transformer in series, a second series circuit connected between a node to which the primary winding of the second transformer and one end of the second switch are connected, and another end of the second switch, the second series circuit including a second
diode, the
smoothing capacitor, and an additional winding of the second transformer, which is connected to the primary winding of the second transformer in series, a reactor connected to both ends of a series circuit in which a secondary winding of the first transformer and a secondary winding of the second transformer are connected in series, and a
control circuit which turns on and off the first and second switches with a
phase difference of half a cycle.