A boost converter control apparatus which is configured to control a boost converter in a motor drive system, said motor drive system comprising: a direct current power supply; a three-phase alternating current motor; an electric power converter disposed between the direct current power supply and the three-phase alternating current motor, the electric power converter including switching circuits (Q3-Q8), each of which corresponds to respective one of three phases of the three-phase alternating current motor, and a smoothing condenser, which is disposed electrically in parallel with the switching circuits (Q3-Q8); and the boost converter disposed between the electric power converter and the direct current power supply, the boost converter boosting a direct current voltage of the direct current power supply and supplying it to the electric power converter, said boost converter control apparatus comprising: an operating device comprising a proportional element, an integral element (113B, 113C) and a derivative element (113D, 113E), the derivative element (113D, 113E) being configured as a bandpass filter, said operating device calculating a PID controlled variable corresponding to an electric current command value of the boost converter for maintaining an output voltage of the boost converter at a command value of an inter-terminal voltage VH of the smoothing condenser; and a controlling device (118, 115) which is configured to control the output voltage of the boost converter on the basis of the calculated PID controlled variable, wherein a cutoff frequency (fc) of the bandpass filter is greater than or equal to an upper limit value of a motor electrical frequency (FBmtr) which is proportional to a rotational speed of the three-phase alternating current motor, and the cutoff frequency is less than a lower limit value of a carrier frequency (fcar) of the electric power converter. a direct current power supply; a three-phase alternating current motor; an electric power converter disposed between the direct current power supply and the three-phase alternating current motor, the electric power converter including switching circuits (Q3-Q8), each of which corresponds to respective one of three phases of the three-phase alternating current motor, and a smoothing condenser, which is disposed electrically in parallel with the switching circuits (Q3-Q8); and the boost converter disposed between the electric power converter and the direct current power supply, the boost converter boosting a direct current voltage of the direct current power supply and supplying it to the electric power converter, said boost converter control apparatus comprising: an operating device comprising a proportional element, an integral element (113B, 113C) and a derivative element (113D, 113E), the derivative element (113D, 113E) being configured as a bandpass filter, said operating device calculating a PID controlled variable corresponding to an electric current command value of the boost converter for maintaining an output voltage of the boost converter at a command value of an inter-terminal voltage VH of the smoothing condenser; and a controlling device (118, 115) which is configured to control the output voltage of the boost converter on the basis of the calculated PID controlled variable, wherein a cutoff frequency (fc) of the bandpass filter is greater than or equal to an upper limit value of a motor electrical frequency (FBmtr) which is proportional to a rotational speed of the three-phase alternating current motor, and the cutoff frequency is less than a lower limit value of a carrier frequency (fcar) of the electric power converter. an operating device comprising a proportional element, an integral element (113B, 113C) and a derivative element (113D, 113E), the derivative element (113D, 113E) being configured as a bandpass filter, said operating device calculating a PID controlled variable corresponding to an electric current command value of the boost converter for maintaining an output voltage of the boost converter at a command value of an inter-terminal voltage VH of the smoothing condenser; and a controlling device (118, 115) which is configured to control the output voltage of the boost converter on the basis of the calculated PID controlled variable, wherein a cutoff frequency (fc) of the bandpass filter is greater than or equal to an upper limit value of a motor electrical frequency (FBmtr) which is proportional to a rotational speed of the three-phase alternating current motor, and the cutoff frequency is less than a lower limit value of a carrier frequency (fcar) of the electric power converter.