To prevent excessive consumption of inactive gas and positively prevent intrusion of reaction product gas to a bearing side by controlling the supply flow rate of inactive gas to a shaft seal part appropriate for respective states of processing and non-processing of a device for performing evacuation.

The vacuum pump is equipped with an inactive gas supply means for supplying inactive gas between the shaft seal and the bearing. The inactive gas supply means includes a first gas flow rate regulating means 52 for performing flow rate regulation of inactive gas supplied between the shaft seal and the bearing during processing of a device for performing evacuation, a second gas flow rate regulating means 53 for performing flow rate regulation of inactive gas made to flow between the shaft seal and the bearing during non-processing of the device, and a control means 60 for switching between outputting inactive gas flow rate-regulated by the first gas flow rate regulating means 52 during the processing of the device and outputting inactive gas flow rate-regulated by the second gas flow rate regulating means 53 during the non-processing of the device.