Single diaphragm type pressure gage

The utility model provides a single diaphragm type pressure gage, which comprises a base with an air inlet tube. A diaphragm is arranged on the base, and the diaphragm is compacted by a gage shell which is contained with the base; the center of the diaphragm in the gage shell is axially provided with a spring which is sheathed with a shaft rod, a deflector rod which is butted with the spring is fixed with the shaft rod; a coil spring is arranged at the upper section of the shaft rod, and a gage needle which is linked with the external extending end of the shaft rod is arranged on the top surface of the gage shell. The utility model is characterized in that a pad is arranged between the annular edge of the base and the metal diaphragm, and the lower part of the gage shell with the same thickness is provided with an annular ring hoop with a star-shaped cross section; the base, the pad and the metal diaphragm are inlaid and clamped together by the ring hoop with a star-shaped cross section; the shaft rod is movably inserted in a cylinder seat which is fixed with the metal diaphragm.