The present invention has an object of controlling power consumption by a vacuum pump by varying the number of revolutions of the vacuum pump in accordance with the operating state of a vacuum device.The condition setting part 4 sets the relationship between the operating state of the vacuum device 10 and the rotational speed of the vacuum pump 2 that evacuates the vacuum device 10. This relationship is set to an appropriate value so as to prevent the rotational speed of the vacuum pump 2 from becoming a higher rotational speed than is required. The control part 6, to which external signals S1 through Sn corresponding to the operating state of the vacuum device 10 are input, reads out from the condition setting part 4 and outputs the rotational speed of the vacuum pump 2 corresponding to the external signals. The inverter 8 controls the rotational speed of the vacuum pump based on the output of the control part 6.