A voltage converter control apparatus controls repetitive switching operations of a voltage converter, for conversion between a terminal voltage of a battery as an input-side voltage and a terminal voltage of a power inverter as an output-side voltage, by determining a command value of duty ratio of the switching in accordance with a command value of the output-side voltage. The voltage converter control apparatus sets a normal duty ratio range defining limit values of the duty ratio for normal operation of the voltage converter, with the limit values being determined based upon information including the command value of the output-side voltage.