To provide an electrostatic capacity type absolute pressure detector small-sized, having a smaller hysteresis, high-precision and high-reliability, having an excellent ratio of nondefective assembling, and easily-assemblable.

This is composed of a silicon substrate 6a in which a diaphragm 61 as a movable electrode which is displaced by a pressure, and a recession 62 for forming a capacitor of a fixed gap have been formed, a tabular insulating board B 8a, and an insulating board A 7a provided with an absolute pressure detecting fixed electrode 73, a compensating fixed electrode 77, terminals 74a, etc., and pressure leading holes 71a, etc. And the diaphragm 61 and the fixed electrode 73 form an absolute pressure detecting capacitor of an absolute pressure detecting element 100, and the bottom of the recession 62 and the fixed electrode 77 form a compensating capacitor of a compensating part 200. And a vacuum reference chamber 5a is formed below the diaphragm 61. The electrodes 73, etc., of these capacitors are all led out to the terminals 74, etc., on the upper surface of the insulating board A 7a through the pressure leading holes 71a, etc.