A hollow fiber membrane module is capable of producing washed platelets having a low total protein amount and a high total platelet count from a platelet suspension. The hollow fiber membrane module for washing platelets by removal of impurities from a platelet suspension includes a housing having a platelet suspension inlet, washed platelet outlet, and filtrate outlet and a hollow fiber membrane for filtering the platelet suspension, wherein pores through which the platelets do not pass, while the impurities pass, are formed, which hollow fiber membrane is arranged inside the housing wherein the capacity of the inlet-side space which communicates with the platelet suspension inlet and stores the platelet suspension before being filtered through the hollow fiber membrane in the housing is 30 to 400 mL, and the module water permeability is 50 to 300 mL/Pa/hr.
