Vacuum gauge

A vacuum gauge comprising:

• an introduction tube;
• a diaphragm configured to be displaced by a gas to be measured that is introduced from the introduction tube;
• a piezoelectric element having one end coupled to the diaphragm, and configured to be displaced along with the diaphragm;
• an inner mounting structure to which a circumferential edge of the diaphragm and another end of the piezoelectric element are secured, the inner mounting structure being coupled to the introduction tube;
• and an airtight container configured to airtightly enclose the introduction tube and the inner mounting structure, the inner mounting structure, the introduction tube, and the diaphragm airtightly partitioning a space in the airtight container into a pressure introduction chamber to which the gas to be measured is introduced on one surface side of the diaphragm, and a reference pressure chamber on another surface side of the diaphragm, the reference pressure chamber being set at a high vacuum that is lower than a pressure lower limit of the gas to be measured.