PURPOSE: To provide a compact semiconductor pressure sensor in which pressure can be measured over a wide range at a piezo resistance part and fine variation of pressure can be measured highly accurately over a specific pressure range at a capacitive part by providing a single diaphragm with pressure-sensitive functions of both piezo resistance type semiconductor pressure sensor and capacitive semiconductor pressure sensor.

CONSTITUTION: Pressure-sensitive part of piezo resistance semiconductor pressure sensory i.e., piezo resistors (not shown), a low resistance region 104b for connecting them, and movable electrode 114, i.e., a low resistance region 104a, of a plate capacitor in capacitive semiconductor pressure sensor are provided on one thin diaphragm 109 and a fixed electrode 113, i.e., a poly-Si electrode 106a, of plate capacitor is provided through an air gap on the diaphragm 119.