To provide a step-up converter capable of miniaturizing a reactor more than a conventional one and reducing ripples of an output voltage.

The step-up converter includes a full-bridge circuit having two or more switching arms each having a switching element and converting a DC voltage input by switching of the switching element into an AC voltage, a double voltage circuit for stepping up the voltage into a voltage higher than the DC voltage based on the AC voltage generated by the full-bridge circuit, and a control section for controlling the switching of the switching element of the full-bridge circuit.