Fluid control valve

A fluid control valve comprising:

• an operation rod;
• a valve element coupled to the operation rod;
• a valve seat which the valve element makes contact with and separation from;
• and
• a diaphragm member located between the operation rod and the valve element,
• the valve element being to be driven by the operation rod to make the contact with and separation in a direction of a central axis of the operation rod to control a control fluid,
• wherein the diaphragm member has a spherical cap shape that is centered on an extension line of the central axis and bulges toward the operation rod, and the diaphragm member is held, at its vertex portion, from both sides in a direction parallel to the central axis by a first holding piece that contacts the diaphragm member from a side of the operation rod and a second holding piece that contacts the diaphragm member from a side of the valve element,
• wherein the first holding piece and the second holding piece each have a circular shape located coaxially with the operation rod, and a diameter of the first holding piece is larger than a diameter of the second holding piece, and
• wherein a surface of the first holding piece, facing the diaphragm member, is a convex spherical surface that bulges toward the diaphragm member and is centered on the central axis.