The present invention minimizes system loss during execution of intermittent boosting. This device for controlling a boost converter is provided with: a target value setting means that sets the target value for an output voltage (VH) such that losses in a power supply system containing a DC power source, the boost converter, and a load device are minimized; an intermittent control means that executes an intermittent process of boost control in a manner so that the output voltage (VH) is maintained in a predetermined range containing the set target value; an average value calculation means that calculates an average value for the output voltage (VH) during the period of execution of the intermittent process; and a target value correction means that corrects the set target value in a manner so that the deviation between the calculated average value and the set target value is reduced.