Nitrogen gas safe supply monitor for mass spectrometry and nitrogen gas generation device

A nitrogen gas safe supply monitor for mass spectrometry (MS) is provided between a compressed air generator and a nitrogen gas separator. Nitrogen gas discharged from the nitrogen gas separator is supplied to an analyzing device such as a mass spectrometer. The nitrogen gas safe supply monitor for MS includes: a gas inlet; a gas outlet; a pipe connecting the gas inlet and the gas outlet; a cutoff valve provided partway in the pipe; a water filter that is provided partway in the pipe and filters water from a gas flowing through the pipe; a water sensor that detects water filtered by the water filter; and a control unit that closes the cutoff valve when the sensor detects water. The control unit may record a date and time when the cutoff valve is closed. Notification means for notifying that the control unit has closed the cutoff valve may be further provided.