A fluid monitoring device detects the flow of fluid through the combination of a sensor and a field source, and the sensor or the field source has an encapsulation film to prevent the fluid from being eroded. This creation can also be applied to seawater cooling devices to detect the inflow of seawater.一種流體監測裝置,透過感測器和場源的搭配,偵測流體的流動,且感測器或場源具有封裝膜,以防止流體的侵蝕。本創作也可應用於海水冷卻裝置,以偵測海水的流入。