A pressure sensor (100) includes a diaphragm (3); a semiconductor chip (1) that includes a plurality of resistors (R1 to R4) constituting a strain gauge and that has a square shape in plan view; four first structures (2a to 2d) each having one end joined to a region of the second main surface of the diaphragm that is deformed when a pressure is applied to a first main surface (1A) of the diaphragm and having other ends respectively connected to four corners of the semiconductor chip, the first structures extend downward to a second main surface (3B); and a second structure (2e) having one end joined to a center (30) of the diaphragm on the second main surface in plan view and having the other end joined to a center (10) of the semiconductor chip in plan view, the second structure extending downward to the second main surface.