An object of the present invention is to prevent “deteriorations,” such as oxidization and deformation of micro solder spheres during storage.The micro solder spheres are packed in a container 2 comprising an air permeable material. A deoxidizing and drying agent 3 to be disposed externally to the container 2 is provided. The container 2 and the deoxidizing and drying agent 3 are placed in a bag member 4 impermeable to air, and the bag member 4 is sealed in an air-tight condition. Before sealing, the bag member 4 may be air evacuated. A plurality of containers 2 may be held by a holding member 5 such that they are fixed in positions relative to each other.