A fluid controller that reduces an increase in cost by additional components or additional processes for setting means, and solves the problem that a set value of an upward movable amount of a stem changes is provided. An upper surface of an outer peripheral edge portion of a diaphragm holder 7 and a lower surface of an inner peripheral edge portion of a holder adapter 15 are formed so as to oppose to each other with a first gap A interposed therebetween. By setting the first gap A to a predetermined value, an upward movable amount of the diaphragm holder 7 is set.