To provide a vacuum pump controller capable of reducing the electric power consumption of a vacuum pump and preventing a harmful influence accompanied with the stop of the pump.

In this vacuum pump controller driving a motor 5 by a controller 3 to exhaust air in a chamber by driving the motor 5 and putting a space 21 inside the chamber into a vacuum condition, whether the chamber 2 is in vacuum control or not is detected by a valve 7 provided in a part of a pipe 6 or either of pressure sensors 9, 10 provided in the front and rear of the valve 7. When the space 21 inside the chamber is in non-vacuum control, the number of revolutions of the motor 5 driving the vacuum pump 4 is put in a low idling condition when compared with the number of revolutions in vacuum control by the controller 3.