PURPOSE: To attain an excellent temperature characteristic by connecting a pressure receiving element and a displacement converting mechanism by a connecting shaft and combining two or more kinds of materials to constitute this connecting shaft.

CONSTITUTION: The constitution of a connecting shaft 18 applied to a pressure transmitter is shown in Fig. In this connecting shaft 18, the first columnar shaft member 19 and the second cylindrical shaft member 20 are formed with different materials, and these two shaft members 19 and 20 are fitted to each other coaxially and are welded in end faces to be joined. For example, the first shaft member 19 is formed with SUS316 (thermal expansion rate of 16× 10-5/°C), and the second shaft member 20 is formed with Ni-SPAN C (thermal expansion rate of 8×10-6/°C). A main body 1 is formed with SUS316 (thermal expansion rate of 16×10-6/°C), and fixed electrode parts 4a and 4b are formed with ceramic (8×10-6/°C), and supporting rings 5a and 5b and moving electrodes 10a and 10b are formed with Ni-SPAN C (8×10-6/°C).