A pressure sensor includes a base having a mounting surface, an elastic member mounted on the mounting surface and forming a dome shape including a convex curved surface, a first pressure-sensitive element placed in a position between the mounting surface and the elastic member and corresponding to a vertex of the convex curved surface and outputting a first detection signal by sensing pressure, a second pressure-sensitive element placed in a position between the mounting surface and the elastic member and corresponding to a peripheral portion of the convex curved surface and outputting a second detection signal by sensing pressure, and a calculator performing a calculation on the first detection signal and the second detection signal, wherein the calculator measures hardness of an object based on a ratio R1-1/2 between the first detection signal and the second detection signal when the object is pressed against the elastic member with a first load.