A capacitance pressure sensor that prevents leakage from outside the sensor to the reference pressure cavity, has a structure that can decrease defects due to leakage compared to conventional technology. An electrode comprising a thin metallic layer is formed on the upper surface of a glass substrate that forms one of the substrates of a pressure sensor and an external electrode is formed on the surface edge of the substrate. In addition, in the region where the silicon substrate is bonded, a feedthrough extending from the electrode to the external electrode is formed, and spine shaped layers with three braches for blocking leakage gas are formed perpendicularly to the feedthrough.