Abstract: A chlorine fluoride feeding device and feeding process are provided that can stably generate industrially applicable chlorine fluoride (ClF), control flow rate, and provide continual feed. The feeding process of chlorine fluoride of this invention is a feeding process to feed chlorine fluoride generated by loading a gas that contains fluorine atoms and a gas that contains chlorine atoms to a flow-type heat reactor or a plasma reactor, and it can stably generate and safely feed chlorine fluoride for a long time by reacting chlorine fluoride that is difficult to pack at a high pressure, such that an amount that can be packed in a gas container such as a gas cylinder is limited, with two or more types of gas materials that can be packed safely in a gas container by liquefaction, or with such gas material and a solid material.