PURPOSE: To provide a battery voltage converter improved so that an electrical quantity of a battery can be effectively used concerning the battery voltage converter in which a voltage of the battery is converted and the voltage is supplied to a load.

CONSTITUTION: A DC voltage converter in which a voltage of a battery is converted and the voltage is supplied to a load comprises DC voltage conversion means A(1) for converting the voltage of a battery A, DC voltage conversion means 13(2) for converting the voltage of a battery B, operating switching means (3) for alternately switching operations of the DC voltage conversion means A(1) and B(2), and switching command generating means (4) for generating a switching command to the operating switching means (3).