To provide a method for preventing powder from scattering as an easily adoptable method at a civil engineering/building site.

This method for preventing powder from scattering is used when the powder 11 contained in a flexible container 1 is loaded into a loading aperture 32 of a mixing installation 3. A cylindrical cover material 4 with an upper and a lower opening 41 and 42 is placed to wrap the suspended flexible container 1 prior to the loading operation and during this operation, the upper opening 41 of the cylindrical cover material 4 is closed and the lower opening 42 is placed on the loading aperture 32 to close the surrounding of the loading aperture 32. Further, after the end of the loading operation, the lower opening 42 is removed from the loading aperture 32 and closed, and the empty flexible container 1 is hermetically closed with the cylindrical cover material 4.