To provide a powder feeding device of a powder freighter allowing enlargement of volume for loading powder in a hold by reducing labor and time of manufacturing and installation, etc. and the cost.

This powder feeding device X of a powder freighter has air slide members 15 to 17 obliquely arranged in combination of a plurality of the members 15 to 17 at the bottom part of the hold 11 to move powder P mounted on flat ventilating sheets 12 to 14 arranged on upper sides to an oblique lower side by blowing air K from the sheets 12 to 14. The air slide members 15 to 17 have flat plates 19, 32 and 37 formed by arranging a plurality of air holes 18, 31 and 18, the ventilating sheets 12 to 14 closely adhered and fixed to the surroundings of the flat plates 19, 32 and 37 by covering the air holes 18, 31 and 18, ducts 20, 33 and 38 to supply compressed air E to the plurality of air holes 18, 31 and 18, and supporting member 21, 22, 34 and 39 for fixing the flat plates 19, 32 and 37 in the hold 11.