A pressure sensor includes a substrate whose top surface is formed in the form of a projection, a first electrode formed on one side of the top surface of the substrate, a second electrode formed on the other side of the top surface and spaced apart from the first electrode; and a dielectric material layer formed on the top surface of the substrate and fills a space between the first electrode and the second electrode. A pressure applied in a direction perpendicular to the top surface of the substrate causes a change in the dielectric constant of the dielectric material layer. The magnitude of the pressure is sensed by detecting a capacitance which changes according to the change in the dielectric constant. The projection forms a stress concentration structure, through which the dielectric constant change amount according to the pressure becomes larger, thereby improving sensitivity of the pressure sensor.