A pressure sensor includes: a base including an outer surface partially or entirely composed of a curved surface; a plurality of electrodes disposed on the outer surface of the base with spaces therebetween and including at least one signal electrode and at least one ground electrode; and at least one variable resistor made from conductive foam elastomer material and configured to be elastically compressed upon application of pressure and such that electric resistance between the signal electrode and the ground electrode decreases as the amount of the compression increases.