To provide a pressure or differential pressure transmitter that has high output stability by relieving a heat sensitive element and a center diaphragm of the influence of tightening of pressure receiving flanges, etc.

A sensor block 1, a center diaphragm block 2, pressure inlet pipes 5, 6, 7, 8, and an electric circuit 9 are enclosed in a housing 10, and liquid isolating diaphragm blocks 3, 4 are secured to one side of the housing 10. Therefore, a pressure sensitive element 17 and a center diaphragm 22 are made to be not affected by the tightening forces of locking bolts 36, 37 locking pressure- receiving flanges 11, 12.