Druckmessvorrichtung

A pressure measuring apparatus comprising a seal diaphragm that separates a fluid to be measured from a pressure transmitting medium that transmits a pressure variation of the fluid to be measured to a pressure detecting section. In such an apparatus, a non-electrically conductive film is coated on a surface of the seal diaphragm which is on the side of the fluid to be measured. As a result of the above construction, the pressure can be measured accurately over a long period of time while preventing hydrogen from passing through the seal diaphragm surely and protecting the seal diaphragm.