Patent ID: 8851296

Claim:
A blood processing filter comprising a sheet-like filter element, an inlet-side flexible container and an outlet-side flexible container that sandwich the filter element and are sealed thereto, an inlet port provided in the inlet-side flexible container for accepting blood before being processed by the filter element, and an outlet port provided in the outlet-side flexible container for discharging blood after being processed by the filter element; the blood processing filter further comprising: a band-shaped first seal part that seals the inlet-side flexible container and the filter element so as to surround the inlet port; and an annular second seal part that seals at least the inlet-side flexible container and the outlet-side flexible container, and that is formed so as to surround the first seal part at a position that is closer to an outer edge than the first seal part; wherein: a valley part corresponding to the first seal part is provided on an outlet side of the filter element; an outlet opening that communicates with an inside of the outlet-side flexible container is formed in the outlet port; at least one portion of the outlet opening is arranged so as to overlap with the valley part, and the outlet side flexible container is formed so as not to be adhered to the filter element by the first seal part.