Diaphragm valve, flow control device, fluid control device, and semiconductor manufacturing device

A diaphragm valve comprising:

• a valve body having a flow path formed therein and a valve chamber recessed from an upper surface of the valve body;
• a diaphragm that is disposed in the valve chamber and elastically deformable to open and close the flow path and adjust an opening degree of the flow path;
• a stem for pressing the diaphragm to elastically deform the diaphragm;
• an actuator for driving the stem;
• and a support that is fixed to the valve body and supports the stem and the actuator;
• the stem and the actuator being arranged in series in this order from the upper surface of the valve body in a direction perpendicular to the upper surface,
• the actuator being positioned such that a lower end portion abuts on a member of the support and a vertical position of an upper end portion is movable,
• the upper end portion of the actuator and the stem being connected via a displacement transmitter extending so as to bypass the actuator,
• wherein the stem comprises a first stem member connected to the displacement transmitter, and a second stem member held by the support so as to be movable in an axial direction via a sleeve, the second stem member has an upper end portion which abuts against a lower end portion of the first stem member, and is driven by the first stem member to press the diaphragm, and
• wherein the upper end portion of the second stem member is in point contact with the lower end portion of the first stem member.