sheet of the filter element and the filter element on the one side and by the internal space as other blood processing filter having a flexible container toward the compartment, the flexible container includes a first container and the second container forming unit forming part disposed opposite across the filter element, forming the first vessel is provided in each section and the second container forming unit, and that the inlet port or the outlet of the blood, the container forming the first seal portion and the filter element with the band-shaped, and so as to surround the first port provided in the container forming unit and a first annular seal portion formed on at least the first and the container forms a seal forming portion and the second container, the second container is formed along the outer edge has an annular portion of the second seal portion formed to surround the first seal , the first container forming unit having a space formed around the filtering portion and the outside of the inner space formed partitioned by the first seal portion, the second container forming unit, jimyeo surrounded by the second seal portion, wherein 1, without being partitioned by the seal portion, having a filter element and disposed opposite the extended space formed in the ambient space forming part, the first vessel is the port forming portion is provided in the filtering space forming part, and also the communicates with the interior space of the compartment on one side by the filter element, and the second is the port container forming portion, is provided on the expansion space forming part, and also communicates with the internal space of the other side partitioned by the filter element characterized in that the expansion space and protrudes beyond the outer surface forming portion.시트형의 필터 요소와, 상기 필터 요소에 의해 내부 공간이 한쪽측과 다른쪽측으로 구획된 가요성 용기를 구비한 혈액 처리 필터로서, 상기 가요성 용기는, 상기 필터 요소를 사이에 두고 대향 배치된 제1 용기 형성부 및 제2 용기 형성부와, 상기 제1 용기 형성부 및 제2 용기 형성부 각각에 마련되며, 혈액의 입구 또는 출구가 되는 포
