PURPOSE: To provide a capacitive pressure sensor which is superior of linearlity and temperature characteristics.

CONSTITUTION: A square-frame-shaped support substrate 1 supporting by a diaphragm 3 made of thin film is formed from a silicon wafer. A recessed part 6 is prepared on the substrate 1 so that the diaphragm 4 may be freely deformed elastically in its thicknesswise direction and a movable electrode electrode 8 made of a conductive layer is formed in the diaphragm. Similarly, another support substrate 2 supporting by a diaphragm 5 is formed. A fixing substrate 3 is made out of a glass substrate and fixing electrodes 12 and 13 are formed on the upper and lower surfaces of the substrate 3, respectively. The substrates 1 and 2 are respectively joined to both surfaces of the substrate 3 while the electrodes 12 and 13 face the electrodes 8 and 9 respectively. In addition, an introducing hole 18 is made in the substrates 2 and 3 to introduce a pressure into the diaphragm 4 on the upper side of the substrate 3, and a differential pressure hole 17 is also made in the substrates 1 and 3 to introduce a reference pressure into the diaphragm 5 on the lower side, resulting in a pressure sensor A.