There is provided a pressure sensor having: a sensor chip (30) which detects a pressure; a base plate (20 (21, 22)) which supports the sensor chip (30); and a support diaphragm (50) which is bonded to the base plate (20 (21, 22)) and supports the base plate (20 (21, 22)), wherein the pressure sensor (1) has a structure in which the support diaphragm (50) is joined to a package (10), and the sensor chip (30) and the base plate (20 (21, 22)) are supported in the package through the support diaphragm (50) alone, thereby constantly and accurately detecting a pressure without being affected by a heat stress caused due to heat from the outside.