Abstract: To provide a partitioning member capable of gaplessly melt-sealing a plurality of containers to the partitioning member even without a support member, provide a partitioning member free from floating of a foreign matter in the container after communicating the containers, and provide a container using the partitioning member, where the contents housed in a plurality of containers can be unfailingly separated before use and respective contents can be easily mixed while keeping the sterile state on use. A partition body 4 for partitioning a hollow part 3 of a partitioning member main body 2 is provided at a portion except for opening ends of the hollow part 3. Also, a support member 10 is melt-sealed to the opening part 12 of the partitioning member main body.