Patent ID: 8429979

Claim:
A capacitance type pressure sensor adapted to measure a pressure by detecting a change of a capacitance between a diaphragm that is displaced by the pressure and a fixed electrode, comprising: a sensor main unit to which the fixed electrode is fixed so as to be exposed to one end side thereof; a diaphragm structure jointed to one end side of the sensor main unit so as to form a sealed space between the diaphragm structure and the sensor main unit; and a fixing member that is jointed to the diaphragm structure in a manner of surrounding a pressure receiving part of the diaphragm structure and is attached to a flow path forming member for forming a flow path to be measured so as to lead a fluid to the pressure receiving part, wherein the diaphragm structure comprises: a flat plane diaphragm main unit for forming the diaphragm; a first ring member having a known thermal expansion coefficient that is jointed to an electrode side circumference in the diaphragm main unit and is connected to one end side of the sensor main unit; and a second ring member having a known thermal expansion coefficient that is jointed to a pressure receiving side circumference in the diaphragm main unit and is connected to the fixing member.