The mechanical bearing monitor is composed of a probe and a pressure indicator. The probe of the detection part is installed in the end nut of the shaft end and fixed on the rear bearing seat at the same time. The detection probe is sealed with pressurized argon. When the bearing is worn radially or axially, the shaft vibrates. Causes the rotor to exceed the normal range, causing the detection part and the end nut to contact and wear, causing the pressure in the monitor to drop (or rise). In addition, since the detection part of the mechanical bearing monitor uses the same material as the pump, it can also monitor the corrosion of the material in the pump. Because the meter body and the probe are filled with fluorine oil, the entire structure guarantees the requirements of pressure resistance.