Blood processing filter and the method for manufacturing the same

A method for manufacturing 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 method comprising:
• an installing step of arranging the inlet-side flexible container and the outlet-side flexible container so as to sandwich the filter element, and arranging a flow channel securing sheet in which a flow channel hole is formed through which blood processed by the filter element passes, between the filter element and the outlet-side flexible container;
• and
• a sealing step of sealing the inlet-side flexible container and the outlet-side flexible container in a state in which the filter element and the flow channel securing sheet are arranged at predetermined positions in the installing step;
• wherein, in the installing step, the outlet port is arranged at a position at which the outlet port is capable of communicating with the flow channel hole of the flow channel securing sheet.