Disclosed is a sphygmomanometer exhaust valve having a valve that functions as a lever, and in which a solenoid moves the point of force of the valve to urge a valve membrane formed at the point of action against a ventilation port. A support member supports the valve while fixing its fulcrum. When no electric current is supplied to the solenoid, the support member holds the valve in a predetermined position in which the ventilation port is open.