[Subject] To provide a pressure sensor capable of implementing cost reduction and miniaturization.[Solving Means] A pressure sensor 1 includes a silicon substrate 2 provided therein with a reference pressure chamber 8, a diaphragm 10, consisting of part of the silicon substrate 2, formed on a surface layer portion of the silicon substrate 2 to partition a reference pressure chamber 8, and an etching stop layer 9 formed on a lower surface of the diaphragm 10 facing the reference pressure chamber 8. A through-hole 11 communicating with the reference pressure chamber 8 is formed on the diaphragm 10, and a filler 13 is arranged in the through-hole 11.