Valve, fluid control device, pressurizing device, and sphygmomanometer

A valve comprising:

• a housing including
• a first wall having at least one first hole connectable to an external pump,
• a second wall having at least one second hole connectable to a component to which a fluid is discharged, and
• a valve chamber held between the first wall and the second wall that oppose each other;
• at least one membrane dividing the valve chamber into a space facing the first wall and a space facing the second wall;
• and
• a communicating passage connecting the space facing the first wall and the space facing the second wall to each other,
• wherein the second wall has a third hole being connectable to an outside of the housing and allowing the fluid to flow out from the valve chamber, and
• wherein, when viewed in a first direction of the housing in which the first wall, the membrane, and the second wall are arranged,
• the membrane, an opening surface of the first hole facing the valve chamber, and an opening surface of the third hole facing the valve chamber overlap one another,
• the communicating passage overlaps neither the opening surface of the first hole facing the valve chamber nor the opening surface of the third hole facing the valve chamber, and
• the opening surface of the first hole facing the valve chamber and the opening surface of the third hole facing the valve chamber at least partially overlap each other.