A boost converter control method in one aspect of the present invention is the control method of the boost converter that boosts a voltage input from a power supply and supplies a boosted voltage to a load-side. The control method of the boost converter is securing an output electric power required according to an operation point of a motor connected to the load-side, calculating a lower limit voltage value at which the output voltage of the boost converter does not oscillate, setting a target output voltage of the boost converter to a value equal to or higher than the lower limit voltage, and controlling the boost converter so as to output a voltage according to the target output voltage.