PURPOSE: To provide an inexpensive and easily assembled pressure sensor, which can continuously detect a pressure and sharply responds to a minute pressure so as to accomplish highly precise detection.

CONSTITUTION: A pressure sensor is provided with a diaphragm 7, which consists of a thin film dividedly forming two pressure chambers 8, 9, pressure receiving plates 10, 11, which are arranged in an approximately center part of the diaphragm 7 while putting the diaphragm 7 between them and are shifted by accompanying the deformation of the diaphragm 7 according to the pressure difference between the two pressure chambers 10, 11, plate springs 14, 15, by which the pressure receiving plates 10, 11 are elastically supported via shaft members 12, 13 so as to be moved from the both sides, a magnet 18, which is arranged in a substantially tip part of the shaft member 13 suspended in an approximately center of the pressure receiving plate 11 and moves with the pressure receiving plate 11, and a magnetic resistance element 19, which is arranged in the vicinity of the magnet 18 and converts the quantity of electricity into the quantity of electricity complying with the quantity of movement of the magnet 18.