A raw feed feeding device of a jet mill (1), wherein raw feed for grinding is fed to the air injector (15) of the jet mill (1) by a raw feed feeder (61) and discharged into the jet mill (1) together with raw feed carrier air, and a raw feed feeding system (60) for feeding the raw feed to the air injector (15) by the raw feed feeder (61) is formed in a closed structure isolated from the atmosphere, whereby the blow−back of dusty air produced by the open system of the raw feed feeder of the jet mill can be prevented from occurring to improve a working environment, increase a pulverizing capacity, and increase a workability.
