A method for supplying a pyrotechnic material slurry to a container, includes, taking out a pyrotechnic material slurry, stored inside a storage container, from the bottom portion of the storage container or a vicinity thereof, sealing the exposed surface of the pyrotechnic material slurry with a sealing material, and maintaining the sealed state of the pyrotechnic material slurry in the process of supplying the pyrotechnic material slurry to the container.