A control apparatus for the boost converter to reduce the total loss is proposed. The control apparatus for the boost converter which controls the boost converter in a power system, the system has a DC power source having source voltage; the boost converter including a switching device and boosting the source voltage by predetermined boost control including change of switching state of the switching device based on boost instruction voltage and outputs the boosted voltage to a load apparatus; and a voltage detecting device detecting output voltage of the boost converter, the control apparatus has: a boost controlling device performing the boost control; and an intermittent controlling device performing intermittent process of the boost control based on the detected output voltage to keep the output voltage within range including the boost instruction voltage which is used when the last boost control is performed.