Abstract: A pressure sensor which uses a tapered shearing piezoresistance type gage to obtain high output. The components are fabricated to produce a surface of the gage which is protected by an oxide film which is turned into phosphorated silicate glass; a sensor surface which has an MOS structure with a silicon substrate; oxide film and polycrystalline silicon film; with the polycrystalline silicon film being fixed at a potential higher than maximum potential generated by the shearing gate, and the surface of the piezoresistance element are where P-type impurity is diffused to a low density being inverted. Thus, the shearing gage is operated substantially in a bulk, and influence due to impurity ion from an external source is removed. Furthermore, the pressure sensor buffers stress arising within the sensor by use of the polycrystalline silicon film, prevents occurrence of local stress by keeping the passivation film from dropping in surface level, thereby minimizing zero offset of the output and drift.