PRESSURE SENSOR

There is provided a pressure sensing apparatus that does not trap any fluid within its flow path and has a simple construction so that it can be manufactured at reduced cost and has a diaphragm that operates stably. Such a pressure sensing apparatus comprises a sensor holder 21 having a flow path 22 arranged therein and provided with a flat surface area 25 and a sensor receiving hole 23 cut from the outer periphery of the sensor holder to the flat surface area 25 of the flow path 25. The apparatus also comprises a diaphragm 24 that is level with the flat surface area 25 and has an even thickness. A pressure sensor 31 arranged in the sensor receiving hole 23. Since a pressure sensing apparatus having a configuration as described above does not have any recess that can trap fluid within the flow path 22, it does not degrade the purity and cleanliness of the fluid running therethrough, if it is connected to a piping system for fluid that requires purging. Additionally, the fluid running through the flow path 22 of the sensor holder 21 does not produce turbulences because of the streamlined profile of the flow path 22 and, since the diaphragm 24 is integral with the sensor holder, no operation is required to fit the diaphragm 24 to the sensor holder 21 and hermetically seal the sensor holder 21 at the connection of the diaphragm 24.