To provide a pressure sensor for judging the presence of the minute leak of gas in gas equipment or accurately judging whether the pressure adjusting function of a pressure adjusting device is normal.

The sensing electrode 11 and reference electrode 12 on a fixing substrate 10 are perfectly separated by isolation electrodes 13 and a first electrode constituted of the sensing electrode 11, the reference electrode 12 and the isolation electrodes 13 and the fixing substrate having a continuity small hole crossing the first electrode at a right angle are arranged in opposed relation to a diaphragm having a second electrode formed thereto. By this constitution, an electrostatic capacity type pressure sensor excellent in temp. characteristics can be constituted.