To reduce generation of stress due to restraint of a sensor diaphragm to secure expected proof pressure.

Of an area S1 of a peripheral part 11-2c of stopper members 11-2 facing one surface of a sensor diaphragm 1-1, an area S1a on the outer peripheral side is considered as a joint area with the one surface of the sensor diaphragm 11-1, and an area S1b on the inner peripheral side is considered as a non-joint area with the one surface of the sensor diaphragm 11-1. When measuring pressure Pa is considered as measuring pressure on the high pressure side, and measuring pressure Pb is considered as measuring pressure on the low pressure side, when the measuring pressure Pa on the high pressure side is applied to the one surface of the sensor diaphragm 11-1, since the non-joint area S1b is formed between the stopper members 11-2, the sensor diaphragm 11-1 can be distorted without generation of excess tensile stress due to restraint, and thus, stress to be generated to the part is reduced.