Blood treatment filter

A blood treatment filter comprising:

• an inlet-side container member and an outlet-side container member that are sealed;
• a filter element, which filters blood, interposed between the inlet-side container member and the outlet-side container member and filtering blood;
• an inlet port provided toward the inlet-side container member side with respect to the filter element;
• a tubular outlet port provided toward the outlet-side container member side with respect to the filter element, wherein blood introduced from the inlet port is discharged from the outlet port;
• an outlet-side frame sheet disposed between the filter element and the outlet-side container member;
• an annular first seal portion defined by at least the filter element and the outlet-side frame sheet being adhered to each other;
• and
• an annular second seal portion defined by the inlet-side container member, the outlet-side frame sheet, and the outlet-side container member being adhered to each other, and the outlet port being adhered to the outlet-side frame sheet and the outlet-side container member at a position where the outlet port penetrates an outer peripheral edge of the blood filter with respect to a plan view of the blood filter,
• the annular second seal portion surrounding the annular first seal portion with respect to the plan view,
• wherein on an outlet side of the filter element, the filter element and the outlet-side frame sheet are compressed in the first seal portion to form a valley portion that is spaced apart from the outlet-side container member,
• the outlet port includes a protruding portion that is spaced apart from the valley portion and is provided with an opening at least a part of which is adjacent to the valley portion.