Fluorine gas generators are connected with semiconductor manufacturing apparatuses through a gas supplying system including a storage tank that can store a predetermined quantity of fluorine gas generated in the on-site fluorine gas generators. When one or more of the on-site fluorine gas generators are stopped, fluorine gas is supplied to the semiconductor manufacturing apparatuses from the storage tank storing a predetermined quantity of fluorine gas, so as to keep the operations of the semiconductor manufacturing apparatuses. Thereby obtained is a semiconductor manufacturing plant in which fluorine gas generated in the fluorine gas generators can be safely and stably supplied to the semiconductor manufacturing apparatuses, and with superior cost performance.