A pressure micro-sensor is formed by a sandwich of three silicon plates in contact by their periphery, with an interposed insulating layer in order to define an internal cavity. The lower plate (2) includes a thinner region (21) forming a diaphragm, on its internal side. The intermediate plate (1) includes a peripheral region (11) forming a frame coupled to the upper and lower plates by a silicon oxide layer (24, 25), a first stud (13) mounted onto the thinner region of the lower plate, a second stud (14) mounted onto a thick region of the lower plate, and a silicon beam (15) forming a resonator and disposed between the upper surfaces of the first and second studs in front of the upper plate (3). A first electrode (32) is connected to the upper plate, a second electrode (33) is connected to the frame and a third electrode (31) is connected to the second stud.