A DC-DC converter with a snubber circuit, adapted to boost a voltage of a DC power supply, comprising: 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 to both ends of the first switch and including a first reactor, an additional winding of the first transformer, a first diode, and a smoothing capacitor; a second diode connected to one end of the first switch and one end of the smoothing capacitor; a second series circuit connected to both ends of the second switch and including a second reactor, an additional winding of the second transformer, a third diode, and the smoothing capacitor; a fourth diode connected to one end of the second switch and the one end of the smoothing capacitor; a third 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; a third series circuit connected to both ends of the smoothing capacitor and including a snubber capacitor (Cs) and a snubber resistor (Rs); a first snubber diode connected to a node at which the snubber capacitor and the snubber resistor are connected, and to a node at which the first reactor and the additional winding of the first transformer are connected; a second snubber diode connected to the node at which the snubber capacitor and the snubber resistor are connected, and to a node at which the second reactor and the additional winding of the second transformer are connected; and a control circuit adapted to turn on the first switch and the second switch alternately in every 1/2 cycle, to turn off the first switch during an on period of the second switch and to turn off the second switch during an on period of the first switch. 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 to both ends of the first switch and including a first reactor, an additional winding of the first transformer, a first diode, and a smoothing capacitor; a second diode connected to one end of the first switch and one end of the smoothing capacitor; a second series circuit connected to both ends of the second switch and including a second reactor, an additional winding of the second transformer, a third diode, and the smoothing capacitor; a fourth diode connected to one end of the second switch and the one end of the smoothing capacitor; a third 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; a third series circuit connected to both ends of the smoothing capacitor and including a snubber capacitor (Cs) and a snubber resistor (Rs); a first snubber diode connected to a node at which the snubber capacitor and the snubber resistor are connected, and to a node at which the first reactor and the additional winding of the first transformer are connected; a second snubber diode connected to the node at which the snubber capacitor and the snubber resistor are connected, and to a node at which the second reactor and the additional winding of the second transformer are connected; and a control circuit adapted to turn on the first switch and the second switch alternately in every 1/2 cycle, to turn off the first switch during an on period of the second switch and to turn off the second switch during an on period of the first switch.