This pressure sensor comprises: a sensor housing that has an opening having different dimensions in the longer direction and the short direction; a sensor chip which is mounted to the sensor housing so as to cover the opening and forms a diaphragm part; a strain gauge provided to the sensor chip; and a cap member joined to the sensor chip by means of a cap joining agent. Among joining surfaces of the cap joining agent, joining surfaces at opposing longer-direction ends of the diaphragm have a larger joining area than joining surfaces at opposing short-direction ends of the diaphragm. Accordingly, in the pressure sensor, it is possible to prevent the diaphragm from being damaged or the like, and to maintain the pressure detection sensitivity.