PROBLEM TO BE SOLVED: To provide a plasma separation membrane module of high safety suppressing an aging decrease in filtration flow while maintaining a high plasma elimination rate, and suppressing a risk of activating platelets.SOLUTION: The plasma separation membrane module includes: a cylindrical housing having a treated liquid lead-in port and a treated liquid discharge port； a hollow fiber membrane bundle disposed inside the cylindrical housing； a potting part for adhesively fixing the hollow fiber membrane bundle to the cylindrical housing； and a first header (with a filtrate discharge port) and a second header which are fixed in a liquid tight manner to the end of the cylindrical housing, respectively. The hollow fiber membrane bundle is fixed in a state of opening the first header side end face in a major axis direction so as to form a space communicating with the treated liquid lead-in port and the treated liquid discharge port, between itself and the cylindrical housing, and the space contains granules shaped not to pass through the treated liquid discharge port.
