PURPOSE: To heighten detecting accuracy by holding linearity to a pressure difference in electrostatic capacity in an electrostatic capacity type pressure sensor to detect pressure after converting it into a change in the electrostatic capacity and a pressure detector to detect the pressure by using the sensor.

CONSTITUTION: An electrostatic capacity type sensor and a pressure detector are composed of fixed electrodes 11 and 12 which are arranged opposite in parallel with each other and whose interval is increased and decreased according to a difference between two pressures applied individually from the opposite sides of the opposite surfaces, a diaphragm shape plate-like body 2 which is supported in parallel with these fixed electrodes in an area sandwiched between the fixed electrodes 11 and 12 and in which the thickness of the surfaces opposed to the respective fixed electrodes is formed thicker than the periphery of the surfaces and movable electrodes 3 which are formed in areas opposed to the fixed electrodes 1 and 12 on both surfaces of the plate-like body 2 and have electrostatic capacity in proportion to the two pressures between these fixed electrodes.