The utility model discloses a vacuum degree monitoring device of a vacuum circuit breaker. The vacuum degree monitoring device comprises a pulse probe, a signal processing unit, a signal transmission unit, an on-site display and a remote communication interface, wherein the pulse probe, the signal processing unit and the signal transmission unit are sequentially connected, the pulse probe is installed under the vacuum circuit breaker, the signal processing unit comprises an amplification circuit, a band pass filter, a rectification filter circuit and a comparison circuit, and the on-site display and the remote communication interface are installed on the signal transmission unit. The vacuum degree monitoring device of the vacuum circuit breaker detects the abnormity of the vacuum degree of the breaker by detecting the pulse signals emitted by the detection breaker, amplifies the detected pulse signals, filters interference signals and outputs the processed signals to the display for displaying the monitoring result on a real-time basis, thereby achieving the purpose of on-line monitoring.