Structure for use with fluid diaphragm

A diaphragm supporting member attached with:

• a diaphragm that is displaced by pressure of a fluid;
• and a peripheral wall member of which one end surface is attached to a circumferential edge part of the diaphragm, the diaphragm supporting member comprising:
• a base that is adapted to have a top surface and a bottom surface and on the top surface, attached with the other end surface of the peripheral wall member to form an internal space filled with the fluid together with the diaphragm and the peripheral wall member;
• a protruding part that protrudes from the top surface of the base;
• and
• a communicatively connecting path that extends from a bottom surface side of the base toward the diaphragm and communicatively connects the internal space and an outside to each other to flow the fluid, wherein
• on an outer lateral surface of the protruding part, an opening is formed in a part intersecting with an inner lateral surface of the communicatively connecting path, and a part of a fore end inner surface of the communicatively connecting path is formed in the protruding part.